[media] doc-rst: add vivid documentation

Convert it to ReST and add to media/v4l-drivers book.

As the sections here (and on other docs) are numbered,
let's also make this book auto-numbered.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/v4l-drivers/index.rst

@@ -17,6 +17,7 @@ License".
 
 .. toctree::
 	:maxdepth: 5
+	:numbered:
 
 	fourcc
 	cardlist
@@ -40,5 +41,6 @@ License".
 	si476x
 	soc-camera
 	uvcvideo
+	vivid
 	zoran
 	zr364xx