drm/i915/display: Expose sharpness strength property

drm/i915/display: Expose sharpness strength property

Expose the drm crtc sharpness strength property which will enable
or disable the sharpness/casf based on user input. With this user
can set/update the strength of the sharpness or casf filter.

v2: Update subject[Ankit]

Signed-off-by: Nemesa Garg <nemesa.garg@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20251028120747.3027332-11-ankit.k.nautiyal@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>