inet netfilter: Remove hook from ip6t_do_table, arp_do_table, ipt_do_table

The values of ops->hooknum and state->hook are guaraneted to be equal
making the hook argument to ip6t_do_table, arp_do_table, and
ipt_do_table is unnecessary. Remove the unnecessary hook argument.

In the callers use state->hook instead of ops->hooknum for clarity and
to reduce the number of cachelines the callers touch.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>