headers_check fix: linux/dlm_plock.h

fix the following 'make headers_check' warning:

  usr/include/linux/dlm_plock.h:25: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>

include/linux/dlm_plock.h

@@ -9,6 +9,8 @@
 #ifndef __DLM_PLOCK_DOT_H__
 #define __DLM_PLOCK_DOT_H__
 
+#include <linux/types.h>
+
 #define DLM_PLOCK_MISC_NAME		"dlm_plock"
 
 #define DLM_PLOCK_VERSION_MAJOR	1