UPSTREAM: iptables: use match, target and data copy_to_user helpers

Convert iptables to copying entries, matches and targets one by one,
using the xt_match_to_user and xt_target_to_user helper functions.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Bug: 120612905
Change-Id: I8e23c9f0566ed9eb895ae626760efccd3bf5c24e
(cherry picked from commit f77bc5b23fb1af51fc0faa8a479dea8969eb5079)
Signed-off-by: Hridya Valsaraju <hridya@google.com>