drm/msm/sde: correct scale offset for some gamut modes

Different gamut modes uses different scale/offset registers, and the
size of the scale/offset registers are also different.
This change corrects the scale/offset register selection for gamut
5x5x5 and 13x13x13b modes.

Change-Id: I219f4a1b27e3e7485b71749cedc2af4a321f42f1
Signed-off-by: Ping Li <pingli@codeaurora.org>