modesetting: Add support for the GAMMA_LUT and CTM properties
In drm, the GAMMA_LUT property provides a larger gamma ramp that can be used to support more precise color ramps, and CTM (the color tranform matrix) can be used to adjust colors between color channels. The drm core code requires that clients use the GAMMA_LUT property when setting the CTM, which is why these two properties are tied together in this series.
This series exposes GAMMA_LUT through the RandR 1.2 gamma ramp interface, and exposes CTM via a RandR output property.