Update copyright line to 2015
diff --git a/include/polarssl/debug.h b/include/polarssl/debug.h
index 042cabb..7032fb6 100644
--- a/include/polarssl/debug.h
+++ b/include/polarssl/debug.h
@@ -3,7 +3,7 @@
  *
  * \brief Debug functions
  *
- *  Copyright (C) 2006-2011, ARM Limited, All Rights Reserved
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
  *
  *  This file is part of mbed TLS (https://polarssl.org)
  *