[DellEMC-Z9264f-C64] Add PFC support for z9264f (#2893)

This commit adds new code and JSON file to support PFC and
broadcom recommended MMU setting for PFC feaure on z9264f
(100G) T1 support. The buffers_defaults_t1.json file has
the broadcom recommended values for T1 configuration.
Unit tested and verified by running the JSON file and checking
the hardware registers and table in broadcom. The settings in
the hardware is reflecting the broadcom recommended values.

Signed-off-by: Harish Venkatraman <harish_venkatraman@dell.com>

device/dell/x86_64-dellemc_z9264f_c3538-r0/DellEMC-Z9264f-C64/buffers.json.j2

@@ -0,0 +1,2 @@
+{%- set default_topo = 't1' %}
+{%- include 'buffers_config.j2' %}

device/dell/x86_64-dellemc_z9264f_c3538-r0/DellEMC-Z9264f-C64/buffers_defaults_t1.j2

@@ -0,0 +1,47 @@
+
+{%- set default_cable = '40m' %}
+
+{%- macro generate_port_lists(PORT_ALL) %}
+    {# Generate list of ports #}
+    {%- for port_idx in range(0,64) %}
+        {%- if PORT_ALL.append("Ethernet%d" % (port_idx*4)) %}{%- endif %}
+    {%- endfor %}
+{%- endmacro %}
+
+{%- macro generate_buffer_pool_and_profiles() %}
+    "BUFFER_POOL": {
+        "ingress_lossless_pool": {
+            "size": "34859968",
+            "type": "ingress",
+            "mode": "dynamic",
+            "xoff": "7847424"
+        },
+        "egress_lossy_pool": {
+            "size": "29631680",
+            "type": "egress",
+            "mode": "dynamic"
+        },
+        "egress_lossless_pool": {
+            "size": "43481152",
+            "type": "egress",
+            "mode": "static"
+        }
+    },
+    "BUFFER_PROFILE": {
+        "ingress_lossy_profile": {
+            "pool":"[BUFFER_POOL|ingress_lossless_pool]",
+            "size":"0",
+            "dynamic_th":"3"
+        },
+        "egress_lossless_profile": {
+            "pool":"[BUFFER_POOL|egress_lossless_pool]",
+            "size":"1518",
+            "static_th":"10870288"
+        },
+        "egress_lossy_profile": {
+            "pool":"[BUFFER_POOL|egress_lossy_pool]",
+            "size":"1518",
+            "dynamic_th":"3"
+        }
+    },
+{%- endmacro %}

device/dell/x86_64-dellemc_z9264f_c3538-r0/DellEMC-Z9264f-C64/pg_profile_lookup.ini

@@ -0,0 +1,17 @@
+# PG lossless profiles.
+# speed cable size    xon  xoff threshold xon_offset
+  10000  5m   1248    2288 35776  -3        2288
+  25000  5m   1248    2288 53248  -3        2288
+  40000  5m   1248    2288 66560  -3        2288
+  50000  5m   1248    2288 90272  -3        2288
+ 100000  5m   1248    2288 165568 -3        2288
+  10000  40m  1248    2288 37024  -3        2288
+  25000  40m  1248    2288 53248  -3        2288
+  40000  40m  1248    2288 71552  -3        2288
+  50000  40m  1248    2288 96096  -3        2288
+ 100000  40m  1248    2288 177632 -3        2288
+  10000  300m 1248    2288 46176  -3        2288
+  25000  300m 1248    2288 79040  -3        2288
+  40000  300m 1248    2288 108160 -3        2288
+  50000  300m 1248    2288 141856 -3        2288
+ 100000  300m 1248    2288 268736 -3        2288

device/dell/x86_64-dellemc_z9264f_c3538-r0/DellEMC-Z9264f-C64/qos.json.j2

@@ -0,0 +1 @@
+{%- include 'qos_config.j2' %}