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-device.c b/drivers/media/video/v4l2-device.c
index ffb425f..e1520bc 100644
--- a/drivers/media/video/v4l2-device.c
+++ b/drivers/media/video/v4l2-device.c
@@ -83,8 +83,19 @@
 	v4l2_device_disconnect(v4l2_dev);
 
 	/* Unregister subdevs */
-	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list)
+	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 		v4l2_device_unregister_subdev(sd);
+		if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
+			struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+			/* We need to unregister the i2c client explicitly.
+			   We cannot rely on i2c_del_adapter to always
+			   unregister clients for us, since if the i2c bus
+			   is a platform bus, then it is never deleted. */
+			if (client)
+				i2c_unregister_device(client);
+		}
+	}
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister);