[NETFILTER]: {ip,ip6}_tables: reformat to eliminate differences

Reformat ip_tables.c and ip6_tables.c in order to eliminate non-functional
differences and minimize diff output.

This allows to get a view of the real differences using:

sed -e 's/IP6T/IPT/g' \
    -e 's/IP6/IP/g' \
    -e 's/INET6/INET/g' \
    -e 's/ip6t/ipt/g' \
    -e 's/ip6/ip/g' \
    -e 's/ipv6/ip/g' \
    -e 's/icmp6/icmp/g' \
    net/ipv6/netfilter/ip6_tables.c | \
    diff -wup /dev/stdin net/ipv4/netfilter/ip_tables.c

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>