drm/amd/display: Fix CSC remap matrix not being applied on dcn30

drm/amd/display: Fix CSC remap matrix not being applied on dcn30

[Why]
DCN3 has two gamut remap matrices. When using CSC adjustment the CM
remap is set to bypass and MPCC remap is used. However to bypass CM
some state in the context is modified and not restored correctly
resulting in subsequent calls to disable MPCC remap as well.

[How]
Fix logic for save/restore of remap enable flag when programming MPCC
remap matrix.

Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>