drm/amd/display: Add DCN3 Command Table Helpers

-Handle DCN3 cases for bios parser and command tables
-Add command function tables for DCN3

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>