[media] ati_remote: parent input devices to usb interface

Parent the input devices to usb_interface instead of usb_device. This
fixes (at least) persistent input device nodes.

Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>