drm/amd/display: Add PState change high hook for DCN32

For some reason, we missed the PState check for DCN32 which may cause
issues for clock transition. This commit add that required hook.

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>