headers_check fix: linux/genetlink.h

fix the following 'make headers_check' warning:

  usr/include/linux/genetlink.h:12: found __[us]{8,16,32,64} type without #include <linux/types.h>

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
diff --git a/include/linux/genetlink.h b/include/linux/genetlink.h
index 7da02c9..b834ef6 100644
--- a/include/linux/genetlink.h
+++ b/include/linux/genetlink.h
@@ -1,6 +1,7 @@
 #ifndef __LINUX_GENERIC_NETLINK_H
 #define __LINUX_GENERIC_NETLINK_H
 
+#include <linux/types.h>
 #include <linux/netlink.h>
 
 #define GENL_NAMSIZ	16	/* length of family name */