Fixes warning on compilation of iptables matches/targets

This changes the type of arguments as follows
- ipt_ip * -> void *
- ipt_entry * -> void *

This patch doesn't change multiport, DNAT, SNAT, MASQUERADE, REDIRECT
because these need more changes (casting void * variable with intended type)
diff --git a/extensions/libipt_pkttype.c b/extensions/libipt_pkttype.c
index 9f09419..568aaab 100644
--- a/extensions/libipt_pkttype.c
+++ b/extensions/libipt_pkttype.c
@@ -86,7 +86,7 @@
 }
 
 static int parse(int c, char **argv, int invert, unsigned int *flags,
-      const struct ipt_entry *entry,
+      const void *entry,
       unsigned int *nfcache,
       struct xt_entry_match **match)
 {
@@ -131,7 +131,7 @@
 	printf("%d ", info->pkttype);	/* in case we didn't find an entry in named-packtes */
 }
 
-static void print(const struct ipt_ip *ip, const struct xt_entry_match *match, int numeric)
+static void print(const void *ip, const struct xt_entry_match *match, int numeric)
 {
 	struct ipt_pkttype_info *info = (struct ipt_pkttype_info *)match->data;
 	
@@ -139,7 +139,7 @@
 	print_pkttype(info);
 }
 
-static void save(const struct ipt_ip *ip, const struct xt_entry_match *match)
+static void save(const void *ip, const struct xt_entry_match *match)
 {
 	struct ipt_pkttype_info *info = (struct ipt_pkttype_info *)match->data;