netfilter: nf_tables: use rcu chain hook list iterator from netlink dump path

[ Upstream commit 4ffcf5ca ]

Lockless iteration over hook list is possible from netlink dump path,
use rcu variant to iterate over the hook list as is done with flowtable
hooks.

Fixes: b9703ed4 ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Reported-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>