[media] doc-rst: Fix some Sphinx warnings

Fix all remaining media warnings with ReST that are fixable
without changing at the Sphinx code.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/Documentation/media/v4l-drivers/tm6000-cardlist.rst b/Documentation/media/v4l-drivers/tm6000-cardlist.rst
index ca08d42..2fbd388 100644
--- a/Documentation/media/v4l-drivers/tm6000-cardlist.rst
+++ b/Documentation/media/v4l-drivers/tm6000-cardlist.rst
@@ -1,5 +1,5 @@
 TM6000 cards list
-===============
+=================
 
 .. code-block:: none