Fix/Update copyright notices; Add SPDX annotation

Let's fix some erroneous/accidential references to wrong license,
update copyright information where applicable and introduce a
SPDX-License-Identifier to all files.

Change-Id: I39af26c6aaaf5c926966391f6565fc5936be21af
diff --git a/tests/vty/vty_test.c b/tests/vty/vty_test.c
index 2542baf..42646eb 100644
--- a/tests/vty/vty_test.c
+++ b/tests/vty/vty_test.c
@@ -1,9 +1,11 @@
-/* (C) 2013 by Jacob Erlbeck <jerlbeck@sysmocom.de>
+/* (C) 2013 by sysmocom - s.f.m.c. GmbH, Author: Jacob Erlbeck <jerlbeck@sysmocom.de>
  * All Rights Reserved
  *
- * This program is iree software; you can redistribute it and/or modify
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or
+ * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,