drm/amd/display: Remove OPTC lock check

At some point, we decided to blank HUBP during pixel data blank, and to
handle that, we added some OPTC lock checks. Later, we realized that
this change caused multiple regression, and we removed it. Nevertheless,
we still have some leftovers that might affect some ASIC behavior, and
this commit drops those changes to keep the code consistent.

Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>