media: digitv: use the newer dvb-usb macros for USB device

In order to make the drivers under dvb-usb more homogeneous,
use the new macro.

Link: https://lore.kernel.org/linux-media/68de8820a361e61c25bf7402acac71b3770ff906.1648499509.git.mchehab@kernel.org


Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>