drm/msm/sde: LTM feature enhancement

1) In case of LTM histogram event notification, report the display
width/height, LTM phase info and ROI info to user space as well.

2) Move the buffer re-collection from LTM histogram event
notification to hist disable function. This is for cases that LTM
histogram interrupt may not be fired when device enters suspend
state right after histogram disable.

3) In LTM ROI setting function, if input ROI region exceeds the
display width and height, crop the ROI width and height to maximum
register values.

Change-Id: I179b9b0d0f654bfe51ef5c07a238b9d7171f43bb
Signed-off-by: Ping Li <pingli@codeaurora.org>