can: gs_usb: rewrap error messages

This patch rewraps the arguments of netdev_err() to make full use of
the standard line length of 80 characters.

Link: https://lore.kernel.org/all/20220309124132.291861-6-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>