drm/msm/sde: handle pm_resume commit correctly

PM_suspend/resume functionality needs atomic state to be saved during
suspend and needs to be reapplied at resume time. But the state saved
during suspend is partially invalid, so we need to fix it before commit.
Use helper function fom the framework to take care of this.

Signed-off-by: Abhijit Kulkarni <kabhijit@codeaurora.org>
Change-Id: I83471c95114c5852d252c866fc4c21aaf4044893