[media] af9015: switch to new DVB-USB

Almost all hacks are now removed and much less code.
Reducing af9015 driver code from 2084 to 1609, it is almost
500 LOC less!

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>