[202012] [cherry-pick] Add extra lossy PG profile for ports between T1 and T2

[bingwang-ms]

Why I did it

This PR is to cherry-pick #11157 to 202012 branch after resolving conflicts.
This PR brings two changes

1. Add lossy PG profile for PG2 and PG6 on T1 for ports between T1 and T2.
   After PR Update qos config to clear queues for bounced back traffic #10176 , the DSCP_TO_TC_MAP and TC_TO_PG_MAP is updated when remapping is enable

• DSCP_TO_TC_MAP

Before	After	Why do this change
"2" : "1"	"2" : "2"	Only change for leaf router to map DSCP 2 to TC 2 as TC 2 will be used for lossless TC
"6" : "1"	"6" : "6"	Only change for leaf router to map DSCP 6 to TC 6 as TC 6 will be used for lossless TC

• TC_TO_PRIORITY_GROUP_MAP

Before	After	Why do this change
"2" : "0"	"2" : "2"	Only change for leaf router to map TC 2 to PG 2 as PG 2 will be used for lossless PG
"6" : "0"	"6" : "6"	Only change for leaf router to map TC 6 to PG 6 as PG 6 will be used for lossless PG

So, we have two new lossy PGs (2 and 6) for the T2 facing ports on T1, and two new lossless PGs (2 and 6) for the T0 facing port on T1.
However, there is no lossy PG profile for the T2 facing ports on T1. The lossless PGs for ports between T1 and T0 have been handled by buffermgrd .Therefore, We need to add lossy PG profiles for T2 facing ports on T1.

We don't have this issue on T0 because PG 2 and PG 6 are lossless PGs, and there is no lossy traffic mapped to PG 2 and PG 6

2. Map port level TC7 to PG0
   Before the PCBB change, DSCP48 -> TC 6 -> PG 0.
   After the PCBB change, DSCP48 -> TC 7 -> PG 7
   Actually, we can map TC7 to PG0 to save a lossy PG.

How I did it

Update the qos and buffer template.

How to verify it

Verified by UT.

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205

Description for the changelog

1. Add extra lossy PG profile for ports between T1 and T2
2. Map TC7->PG0

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[neethajohn]

@bingwang-ms, do we still need this PR. Weren't these changes included in #11132?

[bingwang-ms]

Change already included in #11132