[media] bt819: the ioctls in the header are internal to the kernel

Remove bt819.h from ioctl-number.txt and make a note in the header
that these ioctls are for internal use only.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/media/bt819.h b/include/media/bt819.h
index 38f666b..8025f4b 100644
--- a/include/media/bt819.h
+++ b/include/media/bt819.h
@@ -26,7 +26,10 @@
 /* v4l2_device notifications. */
 
 /* Needed to reset the FIFO buffer when changing the input
-   or the video standard. */
+   or the video standard.
+
+   Note: these ioctls that internal to the kernel and are never called
+   from userspace. */
 #define BT819_FIFO_RESET_LOW 	_IO('b', 0)
 #define BT819_FIFO_RESET_HIGH 	_IO('b', 1)