drm/amd/display: make sure pipe power gating reach requested hw state

drm/amd/display: make sure pipe power gating reach requested hw state

[why]
display mapping change will involved pipe power gating on and off.
when doing this too fase, sometimes usbc will have no display.
check HW status, it is still in pipe power gating.

[how]
insert polling HW status to make sure the required state reached.
also add dal registry key handling.

Reviewed-by: Sung joon Kim <Sungjoon.Kim@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>