Few more python3 compatibility changes, PEP8 standard changes and add missing methods in PDDF common base APIs (#7021)

#### Why I did it
- Python3 compatibility changes for PDDF eeprom class
- Adding API for temperature in PDDF psu class
- PEP8 standard changes and adding missing method in PDDF sfp class

#### How I did it
- Using python3 to invoke the sonic_platform module in PDDF based platform
- Running autopep8 tool to comply to PEP8 standards

platform/pddf/platform-api-pddf-base/sonic_platform_pddf_base/pddf_eeprom.py

@@ -6,7 +6,6 @@
 
 try:
     from sonic_eeprom import eeprom_tlvinfo
-    import binascii
 except ImportError as e:
     raise ImportError(str(e) + "- required module not found")
 
@@ -70,42 +69,42 @@ class PddfEeprom(eeprom_tlvinfo.TlvInfoDecoder):
         (is_valid, results) = self.get_tlv_field(self.eeprom_data, self._TLV_CODE_SERIAL_NUMBER)
         if not is_valid:
             return "N/A"
-        return results[2]
+        return results[2].decode('ascii')
 
     def base_mac_addr(self):
         (is_valid, t) = self.get_tlv_field(self.eeprom_data, self._TLV_CODE_MAC_BASE)
         if not is_valid or t[1] != 6:
             return super(TlvInfoDecoder, self).switchaddrstr(e)
 
-        return ":".join([binascii.b2a_hex(T) for T in t[2]])
+        return ":".join(["{:02x}".format(T) for T in t[2]]).upper()
 
     def modelstr(self):
         (is_valid, results) = self.get_tlv_field(self.eeprom_data, self._TLV_CODE_PRODUCT_NAME)
         if not is_valid:
             return "N/A"
 
-        return results[2]
+        return results[2].decode('ascii')
 
     def part_number_str(self):
         (is_valid, results) = self.get_tlv_field(self.eeprom_data, self._TLV_CODE_PART_NUMBER)
         if not is_valid:
             return "N/A"
 
-        return results[2]
+        return results[2].decode('ascii')
 
     def serial_str(self):
         (is_valid, results) = self.get_tlv_field(self.eeprom_data, self._TLV_CODE_SERVICE_TAG)
         if not is_valid:
             return "N/A"
 
-        return results[2]
+        return results[2].decode('ascii')
 
     def revision_str(self):
         (is_valid, results) = self.get_tlv_field(self.eeprom_data, self._TLV_CODE_DEVICE_VERSION)
         if not is_valid:
             return "N/A"
 
-        return results[2]
+        return results[2].decode('ascii')
 
     def system_eeprom_info(self):
         """

platform/pddf/platform-api-pddf-base/sonic_platform_pddf_base/pddf_psu.py

@@ -260,6 +260,24 @@ class PddfPsu(PsuBase):
         color = self.pddf_obj.get_led_color()
         return (color)
 
+    def get_temperature(self):
+        """
+        Retrieves current temperature reading from PSU
+
+        Returns:
+            A float number of current temperature in Celsius up to nearest thousandth
+            of one degree Celsius, e.g. 30.125
+        """
+        device = "PSU{}".format(self.psu_index)
+        output = self.pddf_obj.get_attr_name_output(device, "psu_temp1_input")
+        if not output:
+            return 0.0
+
+        temp1 = output['status']
+
+        # temperature returned is in milli celcius
+        return float(temp1)/1000
+
     def get_input_voltage(self):
         """
         Retrieves current PSU input voltage

platform/pddf/platform-api-pddf-base/sonic_platform_pddf_base/pddf_sfp.py

@@ -83,7 +83,7 @@ QSFP_POWEROVERRIDE_WIDTH = 1
 QSFP_MODULE_THRESHOLD_OFFSET = 128
 QSFP_MODULE_THRESHOLD_WIDTH = 24
 QSFP_CHANNEL_THRESHOLD_OFFSET = 176
-QSFP_CHANNEL_THRESHOLD_WIDTH = 16
+QSFP_CHANNEL_THRESHOLD_WIDTH = 24
 
 
 SFP_TEMPE_OFFSET = 96
@@ -94,8 +94,6 @@ SFP_CHANNL_MON_OFFSET = 100
 SFP_CHANNL_MON_WIDTH = 6
 SFP_MODULE_THRESHOLD_OFFSET = 0
 SFP_MODULE_THRESHOLD_WIDTH = 40
-SFP_CHANNL_THRESHOLD_OFFSET = 112
-SFP_CHANNL_THRESHOLD_WIDTH = 2
 SFP_STATUS_CONTROL_OFFSET = 110
 SFP_STATUS_CONTROL_WIDTH = 1
 SFP_TX_DISABLE_HARD_BIT = 7
@@ -592,8 +590,9 @@ class PddfSfp(SfpBase):
             if sfpd_obj is None:
                 return None
 
-            dom_thres_raw = self.__read_eeprom_specific_bytes(QSFP_MODULE_THRESHOLD_OFFSET, QSFP_MODULE_THRESHOLD_WIDTH)
+            offset = 384
-
+            dom_thres_raw = self.__read_eeprom_specific_bytes(
+                (offset+QSFP_MODULE_THRESHOLD_OFFSET), QSFP_MODULE_THRESHOLD_WIDTH)
             if dom_thres_raw:
                 module_threshold_values = sfpd_obj.parse_module_threshold_values(
                     dom_thres_raw, 0)
@@ -608,8 +607,8 @@ class PddfSfp(SfpBase):
                     xcvr_dom_threshold_info_dict['vcchighwarning'] = module_threshold_data['VccHighWarning']['value']
                     xcvr_dom_threshold_info_dict['vcclowwarning'] = module_threshold_data['VccLowWarning']['value']
 
-            dom_thres_raw = self.__read_eeprom_specific_bytes(
+            dom_thres_raw = self.__read_eeprom_specific_bytes((offset + QSFP_CHANNEL_THRESHOLD_OFFSET),
-                QSFP_CHANNEL_THRESHOLD_OFFSET, QSFP_CHANNEL_THRESHOLD_WIDTH)
+                                                              QSFP_CHANNEL_THRESHOLD_WIDTH)
             if dom_thres_raw:
                 channel_threshold_values = sfpd_obj.parse_channel_threshold_values(
                     dom_thres_raw, 0)
@@ -1040,6 +1039,28 @@ class PddfSfp(SfpBase):
         else:
             return None
 
+    def get_intr_status(self):
+        """
+        Retrieves the interrupt status for this transceiver
+        Returns:
+            A Boolean, True if there is interrupt, False if not
+        """
+        intr_status = False
+
+        # Interrupt status can be checked for absent ports too
+        device = 'PORT{}'.format(self.port_index)
+        output = self.pddf_obj.get_attr_name_output(device, 'xcvr_intr_status')
+
+        if output:
+            status = int(output['status'].rstrip())
+
+            if status == 1:
+                intr_status = True
+            else:
+                intr_status = False
+
+        return intr_status
+
     def reset(self):
         """
         Reset SFP and return all user module settings to their default srate.
@@ -1354,6 +1375,8 @@ class PddfSfp(SfpBase):
         # if self.plugin_data doesn't specify anything regarding Transceivers
         if modpres == '1':
             return True
+        else:
+            return False
 
     def get_model(self):
         """