drm/amd/display: Enable mem low power control for DCN3.1 sub-IP blocks

[WHY]
Sequences to handle powering down these sub-IP blocks are now ready for use

Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Michael Strauss <michael.strauss@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>