Fix copyright lines still mentioning Brainspark
diff --git a/library/ssl_cookie.c b/library/ssl_cookie.c
index 82efc42..de0d108 100644
--- a/library/ssl_cookie.c
+++ b/library/ssl_cookie.c
@@ -1,7 +1,7 @@
 /*
  *  DTLS cookie callbacks implementation
  *
- *  Copyright (C) 2014, Brainspark B.V.
+ *  Copyright (C) 2014-2015, ARM Limited, All Rights Reserved
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
  *