drm/amd/display: Re-enable DPP/HUBP Power Gating

[Why & How]
Bugs preventing DPP/HUBP power gating have been addressed
so this should be reenabled on dcn314 for sufficient
hardware rev versions

Acked-by: Stylon Wang <stylon.wang@amd.com>
Signed-off-by: Daniel Miess <daniel.miess@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>