drm/xe: Add a helper for DRM device-lifetime BO create

A helper for managed BO allocations makes it possible to remove specific
"fini" actions and will simplify the following patches adding ability to
execute a release action for specific BO directly.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>