drm/msm: disp rsc sequence update

This change updates the mode2 entry and exit sequence for sdm8150.
This is based on recommendatation in hardware programming guide
recommendation.

Change-Id: I131678ff0c1293623e1e2e6c50acf0a454261aef
Signed-off-by: Abhijit Kulkarni <kabhijit@codeaurora.org>