drm/amd/display: Disable FEC if DSC not supported for EDP

[WHY]
Screen was seen corrupted for a few ms
when switching both ways. There was also
not enough bandwidth for HDR to be
enabled in HG disabled mode.
This was due to FEC being
enabled although DSC was not supported
or disabled for the EDP.

[HOW]
Check for EDP DSC support in DC caps
or if DSC should be disabled for EDP
before enabling FEC for EDP.

Reviewed-by: Harry Vanzylldejong <harry.vanzylldejong@amd.com>
Reviewed-by: Evgenii Krasnikov <Evgenii.Krasnikov@amd.com>
Reviewed-by: Nicholas Choi <Nicholas.Choi@amd.com>
Acked-by: Pavle Kotarac <Pavle.Kotarac@amd.com>
Signed-off-by: Iswara Nagulendran <inagulen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>