media: dev-teletext.rst: remove obsolete teletext interface

The teletext interface has been dead for years now, just
remove it.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/media/uapi/v4l/dev-teletext.rst

-.. Permission is granted to copy, distribute and/or modify this
-.. document under the terms of the GNU Free Documentation License,
-.. Version 1.1 or any later version published by the Free Software
-.. Foundation, with no Invariant Sections, no Front-Cover Texts
-.. and no Back-Cover Texts. A copy of the license is included at
-.. Documentation/media/uapi/fdl-appendix.rst.
-..
-.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
-
-.. _ttx:
-
-******************
-Teletext Interface
-******************
-
-This interface was aimed at devices receiving and demodulating Teletext
-data [:ref:`ets300706`, :ref:`itu653`], evaluating the Teletext
-packages and storing formatted pages in cache memory. Such devices are
-usually implemented as microcontrollers with serial interface
-(I\ :sup:`2`\ C) and could be found on old TV cards, dedicated Teletext
-decoding cards and home-brew devices connected to the PC parallel port.
-
-The Teletext API was designed by Martin Buck. It was defined in the
-kernel header file ``linux/videotext.h``, the specification is available
-from
-`ftp://ftp.gwdg.de/pub/linux/misc/videotext/ <ftp://ftp.gwdg.de/pub/linux/misc/videotext/>`__.
-(Videotext is the name of the German public television Teletext
-service.)
-
-Eventually the Teletext API was integrated into the V4L API with
-character device file names ``/dev/vtx0`` to ``/dev/vtx31``, device
-major number 81, minor numbers 192 to 223.
-
-However, teletext decoders were quickly replaced by more generic VBI
-demodulators and those dedicated teletext decoders no longer exist. For
-many years the vtx devices were still around, even though nobody used
-them. So the decision was made to finally remove support for the
-Teletext API in kernel 2.6.37.
-
-Modern devices all use the :ref:`raw <raw-vbi>` or
-:ref:`sliced` VBI API.

Documentation/media/uapi/v4l/devices.rst

@@ -24,7 +24,6 @@ Interfaces
     dev-codec
     dev-raw-vbi
     dev-sliced-vbi
-    dev-teletext
     dev-radio
     dev-rds
     dev-sdr