V4L/DVB: videotext: remove this obsolete API

V4L/DVB: videotext: remove this obsolete API

Remove the vtx (aka videotext aka teletext) API from the v4l2 core.
This API was scheduled for removal in kernel 2.6.35.

The vtx device nodes have been superseded by vbi device nodes
for many years. No applications exist that use the vtx support.
Of the two i2c drivers that actually support this API the saa5249
has been impossible to use for a year now and no known hardware
that supports this device exists. The saa5246a is theoretically
supported by the old mxb boards, but it never actually worked.

In summary: there is no hardware that can use this API and there
are no applications actually implementing this API.

The vtx support still reserves minors 192-223 and we would really
like to reuse those for upcoming new functionality. In the unlikely
event that new hardware appears that wants to use the functionality
provided by the vtx API, then that functionality should be build
around the sliced VBI API instead.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>