firmware: set license to GPLv2+

Change-Id: Id4c00159f984976b6d8641900fb64e36a3a30407
diff --git a/firmware/libboard/common/source/board_cstartup_gnu.c b/firmware/libboard/common/source/board_cstartup_gnu.c
index bfe59ad..c46d42f 100644
--- a/firmware/libboard/common/source/board_cstartup_gnu.c
+++ b/firmware/libboard/common/source/board_cstartup_gnu.c
@@ -2,7 +2,8 @@
  *         ATMEL Microcontroller Software Support

  * ----------------------------------------------------------------------------

  * Copyright (c) 2010, Atmel Corporation

- * Copyright (C) 2017, Harald Welte <laforge@gnumonks.org>

+ * Copyright (c) 2017, Harald Welte <laforge@gnumonks.org>

+ * Copyright (c) 2018, sysmocom -s.f.m.c. GmbH, Author: Kevin Redon <kredon@sysmocom.de>

  *

  * All rights reserved.

  *