- First replacement of xyssl by polarssl where needed

diff --git a/include/polarssl/timing.h b/include/polarssl/timing.h
index 32e53e8..630c8ba 100644
--- a/include/polarssl/timing.h
+++ b/include/polarssl/timing.h
@@ -1,8 +1,8 @@
 /**
  * \file timing.h
  */
-#ifndef XYSSL_TIMING_H
-#define XYSSL_TIMING_H
+#ifndef POLARSSL_TIMING_H
+#define POLARSSL_TIMING_H
 
 /**
  * \brief          timer structure