drm/xe: Prevent return with locked vm

Reorder vm_id check after the one for VISIBLE_VRAM. This should
prevent returning with locked vm in error scenario.

Signed-off-by: Pallavi Mishra <pallavi.mishra@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>