drm/amd/display: Fix hard hang if DSC is disabled

We want to calculate the DTB clock values when DSC is enabled; however,
this is not the current behavior implemented in DCN32. Right now, DML is
trying to calculate DSC values even if DSC is disabled; as a result, we
can have a hard hang due to wrong clock calculation. This commit fixes
this issue by moving the calculation after the DSC check.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>