[media] dvb-usb: add support for dvb-usb-adapters that deliver raw payload

Select this feature setting the dvb-usb-adapter caps field with
DVB_USB_ADAP_RECEIVES_RAW_PAYLOAD

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>