a_iface: Add copyright statement (after recent contributions)

Change-Id: I3f5dedb045a9ae9b93b00a8388a73ed77e67f19f
diff --git a/src/libmsc/a_iface.c b/src/libmsc/a_iface.c
index e24d3ad..5605ad1 100644
--- a/src/libmsc/a_iface.c
+++ b/src/libmsc/a_iface.c
@@ -1,4 +1,5 @@
 /* (C) 2017 by sysmocom s.f.m.c. GmbH
+ * (C) 2018 by Harald Welte <laforge@gnumonks.org>
  * All Rights Reserved
  *
  * Author: Philipp Maier