can: gs_usb: use %u to print unsigned values

This patch changes printf modifier to an unsigned int, as the printed
variables are unsigned.

Link: https://lore.kernel.org/all/20210914101005.84394-1-mkl@pengutronix.de


Cc: Roman Valls <brainstorm@nopcode.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>