netfilter: nf_tables: use kfree_rcu(ptr, rcu) to release hooks in clean_net path

Use kfree_rcu(ptr, rcu) variant instead as described by ae089831ff
("netfilter: nf_tables: prefer kfree_rcu(ptr, rcu) variant").

Fixes: f9a43007d3 ("netfilter: nf_tables: double hook unregistration in netns path")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_api.c

@@ -7332,7 +7332,7 @@ static void __nft_unregister_flowtable_net_hooks(struct net *net,
 		nf_unregister_net_hook(net, &hook->ops);
 		if (release_netdev) {
 			list_del(&hook->list);
-			kfree_rcu(hook);
+			kfree_rcu(hook, rcu);
 		}
 	}
 }