[PATCH] Fix ipt_helper compilation

From: florin@iucha.net (Florin Iucha)

Fix compilation of net/ipv4/netfilter/ipt_helper.c by including the
proper header files.

net/ipv4/netfilter/ipt_helper.c

@@ -9,6 +9,7 @@
  */
 #include <linux/module.h>
 #include <linux/skbuff.h>
+#include <linux/netfilter.h>
 #include <linux/netfilter_ipv4/ip_conntrack.h>
 #include <linux/netfilter_ipv4/ip_conntrack_core.h>
 #include <linux/netfilter_ipv4/ip_conntrack_helper.h>