[media] doc-rst: better organize the media books

The uAPI book has 5 parts, but they lost numeration after
conversion to rst. Manually number those parts, and make
the main index with 1 depth, to only show the parts and
the annexes.

At each part, use :maxwidth: 5, in order to show a more
complete index.

While here, fix the cross-references between different
books.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/Documentation/media/v4l-drivers/fimc.rst b/Documentation/media/v4l-drivers/fimc.rst
index d9f950d..3adc19b 100644
--- a/Documentation/media/v4l-drivers/fimc.rst
+++ b/Documentation/media/v4l-drivers/fimc.rst
@@ -62,8 +62,7 @@
 Media device interface
 ~~~~~~~~~~~~~~~~~~~~~~
 
-The driver supports Media Controller API as defined at
-https://linuxtv.org/downloads/v4l-dvb-apis/media_common.html
+The driver supports Media Controller API as defined at :ref:`media_controller`.
 The media device driver name is "SAMSUNG S5P FIMC".
 
 The purpose of this interface is to allow changing assignment of FIMC instances
@@ -89,12 +88,11 @@
 Capture video node
 ~~~~~~~~~~~~~~~~~~
 
-The driver supports V4L2 Video Capture Interface as defined at:
-https://linuxtv.org/downloads/v4l-dvb-apis/devices.html
+The driver supports V4L2 Video Capture Interface as defined at
+:ref:`devices`.
 
 At the capture and mem-to-mem video nodes only the multi-planar API is
-supported. For more details see:
-https://linuxtv.org/downloads/v4l-dvb-apis/planar-apis.html
+supported. For more details see: :ref:`planar-apis`.
 
 Camera capture subdevs
 ~~~~~~~~~~~~~~~~~~~~~~