This fixes potential invalid pointer de-reference, when
media_entity_cleanup() is called after video_unregister_device,
and video device structure memory is already freed.
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>