drm/i915: Include the LUT sizes in the state dump

Dump the sizes of the software LUTs in the state dump. Makes
it a bit easier to see which is present without having to
decode it from the gamma_mode and other bits of state.

v2: Drop a spurious "is" in commit msg (Uma)

Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200925131656.10022-4-ville.syrjala@linux.intel.com