drm/i915: Sort format arrays consistently

Let's try to keep the pixel format arrays somewhat sorted:
1. RGB before YUV
2. smaller bpp before larger bpp
3. X before A
4. RGB before BGR

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191031165652.10868-7-ville.syrjala@linux.intel.com