docs-rst: add package adjustbox

We need adjustbox to allow adjusting the size of tables that
are bigger than the line width. There are quite a few of them
at the media books.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/conf.py b/Documentation/conf.py
index 85e9f16..ab484e5 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -326,6 +326,9 @@
         \\setromanfont{DejaVu Sans}
         \\setmonofont{DejaVu Sans Mono}
 
+	% To allow adjusting table sizes
+	\\usepackage{adjustbox}
+
      '''
 }