netfilter: remove synchronize_net() calls in ip_queue/ip6_queue

nf_unregister_queue_handlers() already does a synchronize_rcu()
call, we dont need to do it again in callers.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

net/ipv4/netfilter/ip_queue.c

@@ -622,7 +622,7 @@ cleanup_ipqnl: __maybe_unused
 static void __exit ip_queue_fini(void)
 {
 	nf_unregister_queue_handlers(&nfqh);
-	synchronize_net();
+
 	ipq_flush(NULL, 0);
 
 #ifdef CONFIG_SYSCTL

net/ipv6/netfilter/ip6_queue.c

@@ -625,7 +625,7 @@ cleanup_ipqnl: __maybe_unused
 static void __exit ip6_queue_fini(void)
 {
 	nf_unregister_queue_handlers(&nfqh);
-	synchronize_net();
+
 	ipq_flush(NULL, 0);
 
 #ifdef CONFIG_SYSCTL