drm/xe/mocs: Add missing RKL handling

RKL should use the same "gen12" MOCS handling as TGL/ADL-S/ADL-P.

Bspec: 45101
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>