drm/amd/display: enable odm + full screen mpo on dcn21

[WHY & HOW]
Enable ODM Combine + Fullscreen MPO on DCN2.1
For lower power consumption in video use cases.

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Signed-off-by: Sung Lee <sung.lee@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>