drm/amd/display: Update Interface to Check UCLK DPM

[Why]
Videos using YUV420 format may result in high power being used.
Disabling MPO may result in lower power usage.
Update interface that can be used to check power profile of a dc_state.

[How]
Allow pstate switching in VBlank as last entry in strategy candidates.
Add helper functions that can be used to determine power level:
-get power profile after a dc_state has undergone full validation

Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Signed-off-by: Austin Zheng <Austin.Zheng@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>