drm/msm/sde: Add dither feature support

Add dither feature interface for default panel dither config and user
dither config.

Change-Id: I2e67a9f1372355724c380e9643921025bf98fc97
Signed-off-by: Ping Li <pingli@codeaurora.org>
Signed-off-by: Narendra Muppalla <NarendraM@codeaurora.org>
15 files changed