Enable `CONFIG_NFT_FIB_IPV6` and `CONFIG_NFT_FIB_IPV4` in lts kernel config
CONFIG_NFT_FIB_IPV6
and CONFIG_NFT_FIB_IPV4
are only enabled on RPis (https://pkgs.alpinelinux.org/contents?file=nft_fib*.ko&path=&name=&branch=v3.10), but they are necessary for reverse path filtering in nftables even on other architectures.