[NETFILTER]: arp_tables: use XT_ALIGN

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter_arp/arp_tables.h

@@ -280,6 +280,6 @@ extern unsigned int arpt_do_table(struct sk_buff *skb,
 				  const struct net_device *out,
 				  struct arpt_table *table);
 
-#define ARPT_ALIGN(s) (((s) + (__alignof__(struct arpt_entry)-1)) & ~(__alignof__(struct arpt_entry)-1))
+#define ARPT_ALIGN(s) XT_ALIGN(s)
 #endif /*__KERNEL__*/
 #endif /* _ARPTABLES_H */