drm/amd/display: Check for DSC support instead of ASIC revision

[why]
This check for ASIC revision is no longer useful and causes
lightup issues after a topology change in MST DSC scenario.
In this case, DSC configs should be recalculated for the new
topology. This check prevented that from happening on certain
ASICs that do, in fact, support DSC.

[how]
Change the ASIC revision to instead check if DSC is supported.

Signed-off-by: Eryk Brol <eryk.brol@amd.com>
Acked-by: Bindu Ramamurthy <bindu.r@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>