drm/i915/display: Add func to compare hw/sw gamma lut

drm/i915/display: Add func to compare hw/sw gamma lut

Add func intel_color_lut_equal() to compare hw/sw gamma
lut values. Since hw/sw gamma lut sizes and lut entries comparison
will be different for different gamma modes, add gamma mode dependent
checks.

v3:  -Rebase
v4:  -Renamed intel_compare_color_lut() to intel_color_lut_equal() [Jani]
     -Added the default label above the correct label [Jani]
     -Corrected smatch warn "variable dereferenced before check"
      [Dan Carpenter]
v5:  -Added condition (!blob1 && !blob2) return true [Jani]
v6:  -Made patch11 as patch3 [Jani]
v8:  -Split patch 3 into 4 patches
     -Optimized blob check condition [Ville]
v9:  -Exclude spilt gamma mode (bdw and ivb platforms)
      as there is exception in way gamma values are written in
      hardware [Ville]
     -Added exception made in commit [Uma]
     -Dropped else, character limit and indentation [Uma]
     -Added multi segmented gama mode for icl+ platforms [Uma]
v10: -Dropped multi segmented mode for icl+ platforms [Jani]
     -Removed references of sw and hw state in compare code [Jani]
     -Dropped inline from func [Jani]

Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1567538578-4489-4-git-send-email-swati2.sharma@intel.com