drm/i915/icl: Add degamma and gamma lut size to gen11 caps

Add the degamma and gamma lut sizes to gen11 capability
structure.

Note: Currently this doesn't account for the extended range gamma
entries and this will be addressed with new segmented gamma ABI
in a future patch.

v2: Reorder the patch as per Maarten's suggestion.

v3: Rebase

v4: Updated commit message with a note as per Matt's suggestion.

v5: No Change.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1549893025-21837-6-git-send-email-uma.shankar@intel.com