drm/xe/mtl: Reduce Wa_14018575942 scope to the CCS engine

drm/xe/mtl: Reduce Wa_14018575942 scope to the CCS engine

The MTL version of Wa_14018575942 has been updated to suggest only
applying the register change on the CCS engine.

Note that DG2 and PVC have a functionally equivalent workaround with
Wa_18018781329; for now that one is still applying to all engines,
although we'll keep an eye on it in case it changes to be CCS-specific
too.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20230728175601.2343755-2-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>