netfilter: arptable_filter: merge forward hook

It's identical to NF_ARP_IN hook.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

net/ipv4/netfilter/arptable_filter.c

@@ -75,16 +75,6 @@ static unsigned int arpt_out_hook(unsigned int hook,
 			     dev_net(out)->ipv4.arptable_filter);
 }
 
-static unsigned int arpt_forward_hook(unsigned int hook,
-				      struct sk_buff *skb,
-				      const struct net_device *in,
-				      const struct net_device *out,
-				      int (*okfn)(struct sk_buff *))
-{
-	return arpt_do_table(skb, hook, in, out,
-			     dev_net(in)->ipv4.arptable_filter);
-}
-
 static struct nf_hook_ops arpt_ops[] __read_mostly = {
 	{
 		.hook		= arpt_in_hook,
@@ -101,7 +91,7 @@ static struct nf_hook_ops arpt_ops[] __read_mostly = {
 		.priority	= NF_IP_PRI_FILTER,
 	},
 	{
-		.hook		= arpt_forward_hook,
+		.hook		= arpt_in_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_ARP,
 		.hooknum	= NF_ARP_FORWARD,