drm/i915/display: Add filter lut values

drm/i915/display: Add filter lut values

Add the register bits related to filter lut values
and helper to load the casf filter lut.

These values are golden values and these value has
to be loaded one time while enabling the casf.

v2: update commit message[Ankit]
v3: Add intel_casf prefix to filter_load fn[Jani]
v4: Define the filter macros here

Signed-off-by: Nemesa Garg <nemesa.garg@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20251028120747.3027332-5-ankit.k.nautiyal@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>