netfilter: remove unnecessary returns from void function()s

This patch removes from net/ netfilter files
all the unnecessary return; statements that precede the
last closing brace of void functions.

It does not remove the returns that are immediately
preceded by a label as gcc doesn't like that.

Done via:
$ grep -rP --include=*.[ch] -l "return;\n}" net/ | \
  xargs perl -i -e 'local $/ ; while (<>) { s/\n[ \t\n]+return;\n}/\n}/g; print; }'
Signed-off-by: NJoe Perches <joe@perches.com>
[Patrick: changed to keep return statements in otherwise empty function bodies]
Signed-off-by: NPatrick McHardy <kaber@trash.net>

net/ipv4/netfilter/ip_queue.c

@@ -461,7 +461,6 @@ __ipq_rcv_skb(struct sk_buff *skb)
 
 	if (flags & NLM_F_ACK)
 		netlink_ack(skb, nlh, 0);
-	return;
 }
 
 static void

net/ipv6/netfilter/ip6_queue.c

@@ -462,7 +462,6 @@ __ipq_rcv_skb(struct sk_buff *skb)
 
 	if (flags & NLM_F_ACK)
 		netlink_ack(skb, nlh, 0);
-	return;
 }
 
 static void

net/netfilter/nf_conntrack_netlink.c

@@ -2109,7 +2109,6 @@ static void __exit ctnetlink_exit(void)
 
 	nfnetlink_subsys_unregister(&ctnl_exp_subsys);
 	nfnetlink_subsys_unregister(&ctnl_subsys);
-	return;
 }
 
 module_init(ctnetlink_init);

net/netfilter/nf_queue.c

@@ -279,7 +279,6 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
 	}
 	rcu_read_unlock();
 	kfree(entry);
-	return;
 }
 EXPORT_SYMBOL(nf_reinject);
 

net/netfilter/xt_time.c

@@ -148,7 +148,6 @@ static void localtime_3(struct xtm *r, time_t time)
 	}
 
 	r->month    = i + 1;
-	return;
 }
 
 static bool