drm/amd/display: Add P-State Keepout to dcn401 Global Sync

drm/amd/display: Add P-State Keepout to dcn401 Global Sync

[WHY&HOW]
OTG has new functionality to allow P-State relative to VStartup. Keepout region
for this should be configured based on DML outputs same as other global sync
params.

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Dillon Varone <dillon.varone@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>