drm/amd/display: Update MPCC if requested

Don't skip MPCC tree updates if requested.

Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Joshua Aberback <Joshua.Aberback@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>