drm/xe/mocs: add MTL mocs

It was incorrectly using dg2_mocs for now.

v2 (MattR):
 - Use REG_GENMASK/REG_FIELD_PREP for bitfields
 - Add bspec references

Bspec: 45101, 45410, 63882
Signed-off-by: Philippe Lecluse <philippe.lecluse@intel.com>
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>