[media] w9966: zero device state after a detach

After a detach zero the whole device state to ensure a clean slate
on the next attach.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/w9966.c

@@ -937,6 +937,7 @@ static void w9966_term(struct w9966 *cam)
 		parport_unregister_device(cam->pdev);
 		w9966_set_state(cam, W9966_STATE_PDEV, 0);
 	}
+	memset(cam, 0, sizeof(*cam));
 }