drm/xe/device: Prefer the drm-managed mutex_init

drm/xe/device: Prefer the drm-managed mutex_init

There's inconsistent use of mutex_init(), in xe_device_create(), with
several of them never calling mutex_destroy() in xe_device_destroy().
Migrate all of them to drmm_mutex_init(), so the destroy part is
automatically called.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20230225002138.1759016-2-lucas.demarchi@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>