drm/i915/casf: Make a proper hw state copy of the sharpness_strength

drm/i915/casf: Make a proper hw state copy of the sharpness_strength

Make a copy of the uapi.sharpness_strength property value in our hw
state. This is how we deal with having proper state for joined pipes.

Reviewed-by: Michał Grzelak <michal.grzelak@intel.com>
Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260407175244.19654-3-ville.syrjala@linux.intel.com