drm/xe: add a flag to bypass multi-tile config from MTCFG reg

Skip reading this register as it is not relevant in the new devices.

Signed-off-by: Koby Elbaz <kelbaz@habana.ai>
Reviewed-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Moti Haimovski <mhaimovski@habana.ai>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>