drm/amd/display: Add IPS control flag

drm/amd/display: Add IPS control flag

[why]
Currently, driver is not aware if IPS is supported. After PMFW helps
implement new message query functionality, driver will set IPS
capability flag.

[how]
Create new SMU hook function to query IPS capability. Based on the cap,
set appropriate flags to false for power-gating purposes. This will
avoid keeping SMU busy and offloading tasks to DMUB/driver.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Sung Joon Kim <sungkim@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>