drm/msm/sde: Update CRTC set feature to use functions pointers

Code complexity checks on SDE driver flagged the color processing
set CRTC feature logic as high complexity. Replace the offending
switch with feature set function pointers to reduce complexity.

Change-Id: Icb4a06ad75a7a3519d0b253274efe5524263174b
Signed-off-by: Christopher Braga <cbraga@codeaurora.org>