drm/i915/display: Add identifiers for driver specific blocks

drm/i915/display: Add identifiers for driver specific blocks

Add macros to identify intel specific color blocks. It will help
in mapping drm_color_ops to intel color HW blocks

v2:- Prefix enums with INTEL_* (Jani, Suraj)
   - Remove unnecessary comments (Jani)
   - Commit message improvements (Suraj)

Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patch.msgid.link/20251203085211.3663374-2-uma.shankar@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>