[DPB] [Mellanox] Fix files for SN4600 platform (#6930)

- Why I did it
Fix the build and fix the SN4600 DPB support

- How I did it
Fix port configuration file for SN4600 based on recent changes

- How to verify it
System bringup is completed, all interfaces are up.
Platform tests suits all is passing.

Author: DavidZagury