V4L/DVB (11673): v4l2-device: unregister i2c_clients when unregistering the v4l2_device.

Until now I relied on i2c_del_adapter to unregister the i2c_clients for
me, however, if the i2c bus is a platform bus then it is never deleted.

So instead I need to unregister i2c clients when unregistering the
v4l2_device.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/v4l2-common.c b/drivers/media/video/v4l2-common.c
index e32de9e..f9647562 100644
--- a/drivers/media/video/v4l2-common.c
+++ b/drivers/media/video/v4l2-common.c
@@ -746,6 +746,7 @@
 		const struct v4l2_subdev_ops *ops)
 {
 	v4l2_subdev_init(sd, ops);
+	sd->flags |= V4L2_SUBDEV_FL_IS_I2C;
 	/* the owner is the same as the i2c_client's driver owner */
 	sd->owner = client->driver->driver.owner;
 	/* i2c_client and v4l2_subdev point to one another */