msm: mdss: restore ROI update after idle power collapse

IOMMU faults were seen during idle power collapse recovery, when
ROI was not full screen in last update before idle.

Fix issue by reconfiguring DAM size based on ROI used in last update.

Change-Id: I94f914155b3fdc6fd29529ef7abafc0035989873
Signed-off-by: Sachin Bhayare <sachin.bhayare@codeaurora.org>
Signed-off-by: Abhijith Desai <desaia@codeaurora.org>