can: fix build dependency

can: fix build dependency

A recent bugfix introduced a new problem with Kconfig dependencies:

WARNING: unmet direct dependencies detected for CAN_DEV
  Depends on [n]: NETDEVICES [=n] && CAN [=m]
  Selected by [m]:
  - CAN [=m] && NET [=y]

Since the CAN core code now links into the CAN device code, that
particular function needs to be available, though the rest of it
does not.

Revert the incomplete fix and instead use Makefile logic to avoid
the link failure.

Fixes: cb2dc6d2869a ("can: Kconfig: select CAN driver infrastructure by default")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512091523.zty3CLmc-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20251204100015.1033688-1-arnd@kernel.org
[mkl: removed module option from CAN_DEV help text (thanks Vincent)]
[mkl: removed '&& CAN' from Kconfig dependency (thanks Vincent)]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>