cosmetic: Update copyright statement, license notice and SPDX

Some of our files didn't have a copyright notice at all, let's add
it.  Also, update the notices in other files and ensure a SPDX
identifier is present in all but the most trivial files.

Change-Id: If7fa19ce484b415bc645e39b3d0d666b44b5f0fd
diff --git a/library/PCUIF_Types.ttcn b/library/PCUIF_Types.ttcn
index 455082a..132b72d 100644
--- a/library/PCUIF_Types.ttcn
+++ b/library/PCUIF_Types.ttcn
@@ -1,10 +1,19 @@
+/* Osmocom PCU Interface Types, as per osmo-pcu/include/osmocom/pcu/pcuif_proto.h
+ * (C) 2018-2019 Harald Welte <laforge@gnumonks.org>
+ * contributions by Vadim Yanitskiy <axilirator@gmail.com>
+ * All rights reserved.
+ *
+ * Released under the terms of GNU General Public License, Version 2 or
+ * (at your option) any later version.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
 module PCUIF_Types {
 
 import from General_Types all;
 import from Osmocom_Types all;
 
-/* Osmocom PCU Interface Types, as per osmo-pcu/include/osmocom/pcu/pcuif_proto.h */
-
 const charstring PCU_SOCK_DEFAULT := "/tmp/pcu_bts";
 const uint32_t PCU_IF_VERSION := 9;