[media] V4L2 spec: document the new V4L2 DV timings ioctls

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
index 184cdfc..765549f 100644
--- a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
@@ -48,6 +48,12 @@
   <refsect1>
     <title>Description</title>
 
+    <note>
+      <title>Experimental</title>
+      <para>This is an <link linkend="experimental"> experimental </link>
+      interface and may change in the future.</para>
+    </note>
+
     <para>This ioctl is used to create buffers for <link linkend="mmap">memory
 mapped</link> or <link linkend="userp">user pointer</link>
 I/O. It can be used as an alternative or in addition to the