drm/msm/sde: Add support for gamut programming with AHB

If sde block supports reg dma, luts can be programmed using the lut dma.
For sde blocks which don't support reg dma, programming has to be done
via ahb interface. Change adds support for ahb programming.

Change-Id: Ie4bc725d128f0f491dbd9a3e422a8a87a6aa26a0
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>