base: remove obsolete nf_conntrack_helper
Parameter was removed in 6.0 and it is not the default anymore:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b118509076b3 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3bb398d925ec