[DPB] [Mellanox] added capability files for SN3420 platform#6020

Merged

lguohan merged 3 commits intosonic-net:masterfrom

vadymhlushko-mlnx:sn3420_dpb_capability_files

Jan 19, 2021

Commits on Nov 24, 2020

[DPB] added capability files for SN3420 platform
vadymhlushko-mlnx
committed

Commits on Dec 15, 2020

[DPB] added split mode for 1 lane ports
vadymhlushko-mlnx
committed

Commits on Dec 22, 2020

[DPB] extended set of speeds for split modes
vadymhlushko-mlnx
committed