[media] v4l2-dev.rst: fix a broken c domain reference

The "struct" were inside the reference, causing it to break.
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/kapi/v4l2-dev.rst

@@ -56,7 +56,7 @@ You should also set these fields of :c:type:`video_device`:
   :c:type:`video_device`->vfl_dir fields are used to disable ops that do not
   match the type/dir combination. E.g. VBI ops are disabled for non-VBI nodes,
   and output ops  are disabled for a capture device. This makes it possible to
-  provide just one :c:type:`v4l2_ioctl_ops struct` for both vbi and
+  provide just one :c:type:`v4l2_ioctl_ops` struct for both vbi and
   video nodes.
 
 - :c:type:`video_device`->lock: leave to ``NULL`` if you want to do all the