can: gs_usb: gs_make_candev(): set netdev->dev_id

The gs_usb driver supports USB devices with more than 1 CAN channel.
Set the "netdev->dev_id" to distinguish between channels in user
space.

Link: https://lore.kernel.org/all/20221007075418.213403-1-mkl@pengutronix.de


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>