media: v4l uAPI: add descriptions for arguments to all ioctls

Several ioctls are missing descriptions for the third argument
of the ioctl() command. They should have a description, as
otherwise the output won't be ok, and will sound like something
is missing.

So, add them.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/Documentation/media/uapi/v4l/vidioc-g-priority.rst b/Documentation/media/uapi/v4l/vidioc-g-priority.rst
index a763988..c28996b 100644
--- a/Documentation/media/uapi/v4l/vidioc-g-priority.rst
+++ b/Documentation/media/uapi/v4l/vidioc-g-priority.rst
@@ -29,7 +29,7 @@
     File descriptor returned by :ref:`open() <func-open>`.
 
 ``argp``
-    Pointer to an enum v4l2_priority type.
+    Pointer to an enum :c:type:`v4l2_priority` type.
 
 
 Description