media: docs: uAPI: Fix documentation of 'which' field for routing ioctls

The routing ioctls documentation incorrectly describes the 'which'
field, due to a bad copy & paste. Fix it.

Fixes: ea73eda5 ("media: Documentation: Add GS_ROUTING documentation")
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst

@@ -72,7 +72,7 @@ On a successful ``VIDIOC_SUBDEV_G_ROUTING`` call the driver updates the
 
     * - __u32
       - ``which``
-      - Format to modified, from enum
+      - Routing table to be accessed, from enum
         :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
     * - struct :c:type:`v4l2_subdev_route`
       - ``routes[]``