can: raw: add support for SO_MARK

Add support for SO_MARK to the CAN_RAW protocol. This makes it
possible to add traffic control filters based on the fwmark.

Link: https://lore.kernel.org/all/20221210113653.170346-1-mkl@pengutronix.de


Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>