can: gs_usb: modify the usb device table to use only the first usb interface

Modified the USB device table to use only the first USB interface, as is
the case with GS USB devices. This allows other GS USB compatible
devices to be more flexible with their remaining interfaces.

Signed-off-by: Maximilian Schneider <max@schneidersoft.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>