kernel: netfilter: chain filters merged into nf_tables.ko

kernel: netfilter: chain filters merged into nf_tables.ko

In mainline kernel commit 02c7b25e5f5 ("netfilter: nf_tables: build-in
filter chain type") all chain filters were merged into one file and into
one kernel module to save some memory. The code protected by these
configuration options CONFIG_NF_TABLES_BRIDGE, CONFIG_NF_TABLES_IPV4,
CONFIG_NF_TABLES_ARP, CONFIG_NF_TABLES_IPV6, CONFIG_NF_TABLES_NETDEV and
CONFIG_NF_TABLES_INET was merged into the nft_chain_filter.c file which
is now always compiled into the nf_tables.ko file.

This only happened in kernel 4.19 and OpenWrt has to select these as
modules in older kennel versions. Mark them as build-in in the kernel
4.19 specific kernel configuration file which will then not be
overwritten by the package specific settings which try to make them
modular again.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>