netfilter: fix userspace header warning

"make headers_check" issued the following warning:

  CHECK   include/linux/netfilter (64 files)
usr/include/linux/netfilter/xt_ipvs.h:19: found __[us]{8,16,32,64} type without #include <linux/types.h>

Fix this by as suggested including linux/types.h.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter/xt_ipvs.h

 #ifndef _XT_IPVS_H
 #define _XT_IPVS_H
 
+#include <linux/types.h>
+
 enum {
 	XT_IPVS_IPVS_PROPERTY =	1 << 0, /* all other options imply this one */
 	XT_IPVS_PROTO =		1 << 1,