libhwc2.1: update panel brightness when brightness level dirty set

Update brightness level 0 in power off mode and clear dirty.  Update
panel brightness when dirty is set and clear dirty after brightness
updated.  Allow HBM and brightness update via drm prop only when GHBM
UDFPS compensation occurs.

Bug: 197479033
Change-Id: I9f3e7cde16ea3c5395881d2e69d65dc035b34087
(cherry picked from commit e3770ba8cfdb8c6e0a21790ece0474f8a77a2ecc)
1 file changed