can: gw: fix typo

This patch fixes a typo found by codespell.

Fixes: 94c23097 ("can: gw: support modification of Classical CAN DLCs")
Link: https://lore.kernel.org/r/20210127085529.2768537-3-mkl@pengutronix.de


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