[Mellanox] [202106] Fix issue: SFP might not be re-initialized after cable plug in (#9387)

- Why I did it
Fix issue: SFP might not be re-initialized after cable plug in. There could be case like:
1. The SFP object was initialized as QSFP type
2. User use adapter to connect a SFP to a QSFP port
3. The SFP object treat the SFP as QSFP and failed to process EEPROM

- How I did it
If a new SFP is plugged, always re-initialize the SFP

- How to verify it
Added unit test case

platform/mellanox/mlnx-platform-api/sonic_platform/chassis.py

@@ -594,10 +594,6 @@ class Chassis(ChassisBase):
         :param port_dict: SFP event data
         :return:
         """
-        # SFP not initialize yet, do nothing
-        if not self.sfp_module_full_initialized:
-            return
-
         from . import sfp
         for index, status in port_dict.items():
             if status == sfp.SFP_STATUS_INSERTED:

platform/mellanox/mlnx-platform-api/tests/test_sfp.py

@@ -1,7 +1,7 @@
 import os
 import sys
 import pytest
-from mock import MagicMock
+from mock import MagicMock, patch
 from .mock_platform import MockFan
 
 test_path = os.path.dirname(os.path.abspath(__file__))
@@ -11,7 +11,7 @@ sys.path.insert(0, modules_path)
 os.environ["PLATFORM_API_UNIT_TESTING"] = "1"
 
 from sonic_py_common import device_info
-from sonic_platform.sfp import SFP, SX_PORT_MODULE_STATUS_INITIALIZING, SX_PORT_MODULE_STATUS_PLUGGED, SX_PORT_MODULE_STATUS_UNPLUGGED, SX_PORT_MODULE_STATUS_PLUGGED_WITH_ERROR, SX_PORT_MODULE_STATUS_PLUGGED_DISABLED
+from sonic_platform.sfp import SFP, SX_PORT_MODULE_STATUS_INITIALIZING, SX_PORT_MODULE_STATUS_PLUGGED, SX_PORT_MODULE_STATUS_UNPLUGGED, SX_PORT_MODULE_STATUS_PLUGGED_WITH_ERROR, SX_PORT_MODULE_STATUS_PLUGGED_DISABLED, SFP_STATUS_INSERTED
 
 from sonic_platform.chassis import Chassis
 
@@ -123,3 +123,16 @@ def test_sfp_get_error_status():
         description = sfp.get_error_description()
 
         assert description == expected_description
+
+
+@patch('sonic_platform.sfp.SFP.reinit')
+def test_reinit_sfps(mock_reinit_sfps):
+    port_dict = {}
+    chassis = Chassis()
+    chassis.reinit_sfps(port_dict)
+    assert not mock_reinit_sfps.called
+
+    port_dict = {1: SFP_STATUS_INSERTED}
+    chassis.reinit_sfps(port_dict)
+    assert mock_reinit_sfps.called
+    assert chassis._sfp_list[0] is not None