[PATCH] dvb: usb doc update

o removed device listing (they are all in the linuxtv wiki now)
o misc updates

Signed-off-by: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Johannes Stezenbach <js@linuxtv.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>