[media] rtl28xxu: Add USB ID for MaxMedia HU394-T

Add USB ID for MaxMedia HU394-T USB DVB-T Multi (FM, DAB, DAB+)
dongle (RTL2832U+FC0012)

In Italy, is branded as "DIKOM USB-DVBT HD"
lsusb:	ID 1b80:d394 Afatech

Signed-off-by: Fabrizio Gazzato <fabrizio.gazzato@gmail.com>
Acked-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>