headers_check fix: linux/gfs2_ondisk.h

fix the following 'make headers_check' warning:

  usr/include/linux/gfs2_ondisk.h:109: 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/gfs2_ondisk.h b/include/linux/gfs2_ondisk.h
index 14d0df0..c56b4bc 100644
--- a/include/linux/gfs2_ondisk.h
+++ b/include/linux/gfs2_ondisk.h
@@ -10,6 +10,8 @@
 #ifndef __GFS2_ONDISK_DOT_H__
 #define __GFS2_ONDISK_DOT_H__
 
+#include <linux/types.h>
+
 #define GFS2_MAGIC		0x01161970
 #define GFS2_BASIC_BLOCK	512
 #define GFS2_BASIC_BLOCK_SHIFT	9