media: v4l2 uapi book: get rid of driver programming's chapter

It doesn't make any sense having a driver programming's chapter
at the uAPI book, as this is related to kernel API. Also,
we now have such kAPI book where V4L2 driver programming is covered.

So, get rid of this left-over.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/v4l/driver.rst

-.. -*- coding: utf-8; mode: rst -*-
-
-.. _driver:
-
-***********************
-V4L2 Driver Programming
-***********************
-
-to do

Documentation/media/uapi/v4l/v4l2.rst

@@ -25,7 +25,6 @@ This part describes the Video for Linux API version 2 (V4L2 API) specification.
     pixfmt
     io
     devices
-    driver
     libv4l
     compat
     user-func