Remove trailing whitespace

Change-Id: I8e24f95a88bef3a59006a89c219871e6156963d7
diff --git a/lib/tun.h b/lib/tun.h
index 95fff26..f63be50 100644
--- a/lib/tun.h
+++ b/lib/tun.h
@@ -1,13 +1,13 @@
-/* 
+/*
  * TUN interface functions.
  * Copyright (C) 2002, 2003 Mondru AB.
  * Copyright (C) 2017 by Harald Welte <laforge@gnumonks.org>
- * 
+ *
  * The contents of this file may be used under the terms of the GNU
  * General Public License Version 2, provided that the above copyright
  * notice and this permission notice is included in all copies or
  * substantial portions of the software.
- * 
+ *
  */
 
 #ifndef _TUN_H