[media] dvb-usb: remove unused files

Those files were left from dvb-usb-v2 development as I have made
mistake during rebase operation.

Reported-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>