They are guarded with NETLINK_DISABLE compile time options,
so if CONFIG_NET is disabled, no linking errors occur.
Bug noticed by Adrian Bunk <bunk@stusta.de>.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>