Why I did it
This SAI change is to Enable TD2 platforms to also be able to handle VFP-based sub-interfaces.
This is the feature that is also needed for TD2 platforms.
How to verify it
Guohan and Team has validated this feature change on TD2 platforms
This is to pick up BRCM SAI 4.3.3.5-2 which contains 2 main changes:
1. hsdk-6.5.21-p1.patch (to address some field problems related to SDK issue.
2. Fix for CS00012097141 (remove some unnecessary debug setting that was causing non functional impacting problem at boot time)
Preliminary tests looks fine. BGP neighbors were all up with proper routes programmed
interfaces are all up
Manually ran the following test cases on S6100 DUT and all passed:
```
ipfwd/test_dir_bcast.py
fib/test_fib.py
vxlan/test_vxlan_decap.py
decap/test_decap.py
fdb/test_fdb.py
```
