can: remove obsolete version strings

As pointed out by Jakub Kicinski here:
http://lore.kernel.org/r/20201009175751.5c54097f@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com


this patch removes the obsolete version information of the different
CAN protocols and the AF_CAN core module.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201012074354.25839-2-socketcan@hartkopp.net


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