netfilter: Add {ipt,ip6t}_osf aliases for xt_osf

There are no these aliases, so kernel can not request appropriate
match table:

$ iptables -I INPUT -p tcp -m osf --genre Windows --ttl 2 -j DROP
iptables: No chain/target/match by that name.

setsockopt() requests ipt_osf module, which is not present. Add
the aliases.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>