Kernels built with a bare CONFIG_NETFILTER and the (relatively) new
CONFIG_TRIM_UNUSED_KSYMS (like our initramfses) have a high probability
of the nf_(un)register_net_hook functions being elided by the unused,
exported symbol trim pass.

So, move to using the base, non-wrapper functions (which can accept
multiple hooks) instead, since those aren't going to be elided.