[NETFILTER]: Fix non-ANSI func. decl.

Fix non-ANSI function declaration:
net/netfilter/nf_conntrack_core.c:1096:25: warning: non-ANSI function declaration of function 'nf_conntrack_flush'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/nf_conntrack_core.c

@@ -1093,7 +1093,7 @@ static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
 			   get_order(sizeof(struct list_head) * size));
 }
 
-void nf_conntrack_flush()
+void nf_conntrack_flush(void)
 {
 	nf_ct_iterate_cleanup(kill_all, NULL);
 }