[media] doc-rst: remove an extra label on V4L2 and CEC parts

There's no need to say: Table of Contents there. Also, this
generates a duplicated caption xref. So, remove, to use the
same format on every part.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/cec/cec-api.rst

@@ -15,7 +15,6 @@ This part describes the CEC: Consumer Electronics Control
 .. toctree::
     :maxdepth: 1
     :numbered:
-    :caption: Table of Contents
 
     cec-intro
     cec-funcs

Documentation/media/uapi/v4l/v4l2.rst

@@ -14,7 +14,6 @@ This part describes the Video for Linux API version 2 (V4L2 API) specification.
 .. toctree::
     :numbered:
     :maxdepth: 1
-    :caption: Table of Contents
 
     common
     pixfmt