Fix kernel build without INET or INET6
Reported by: Gary Jennejohn
Fixes: ff3a85d32411 ("[lltable] Add per-family lltable ...")
Sponsored by: The FreeBSD Foundation
(cherry picked from commit 818952c638a72bd677345fd8ddd05c31b34a2aee)
(cherry picked from commit 85f3c0a1c3762f32dd133deea5951de205e2450b)
Reviewed by: brooks, melifaro
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33718
(cherry picked from commit a6668e31aa3cc855bfb37d6edc05122514592a47)
(cherry picked from commit 1c487a5d3daccb8489c710d8cfabaa83fde1ca58)
Approved by: re (gjb)