V4L/DVB (4748): Fixed oops for Nova-T USB2

When using the remote control with the Nova-T USB there was an Oops because of
the recent DVB-USB-Adapter change.

Signed-off-by: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>