drm/amd/display: fix PSR-SU/DSC interoperability support

Currently, there are issues with enabling PSR-SU + DSC. This stems from
the fact that DSC imposes a slice height on transmitted video data and
we are not conforming to that slice height in PSR-SU regions. So, pass
slice_height into su_y_granularity to feed the DSC slice height into
PSR-SU code.

Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>