drm/msm/sde: update programming sequence for VIG IGC

This change updates programming sequence for VIG IGC on sdm855,
adds data range check for DMA IGC and fix minor input check for
PP dither setup.

Change-Id: I7458c80fe75a577fff9df42c9ce4f783b9bfb7b6
Signed-off-by: Ping Li <pingli@codeaurora.org>