Make sure the subdev pointer is cleared when the subdev object
has been 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>