V4L/DVB (8485): v4l-dvb: remove broken PlanB driver

The PlanB driver has been broken since around May 2004. No one stepped
in to maintain it, so it is now being removed.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Michel Lanners <mlan@cpu.lu>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>