doxygen: Remove copyright block from Doxygen comments

Remove the copyright block from the Doxygen comments, to clean up the
detailed description in the generated Doxygen output. Also, add \file and
\brief tags to all headers in doxygen/input.
diff --git a/doxygen/input/doc_ssltls.h b/doxygen/input/doc_ssltls.h
index 7f104bd..4addfb3 100644
--- a/doxygen/input/doc_ssltls.h
+++ b/doxygen/input/doc_ssltls.h
@@ -1,6 +1,9 @@
 /**
- * @file
- * SSL/TLS communication module documentation file.
+ * \file doc_ssltls.h
+ *
+ * \brief SSL/TLS communication module documentation file.
+ */
+/*
  *
  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
  *  SPDX-License-Identifier: Apache-2.0