Fix some more license versions (GPL2+ instead of GPL2)

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
diff --git a/memory_mapping.h b/memory_mapping.h
index 3f00358..ef72b0a 100644
--- a/memory_mapping.h
+++ b/memory_mapping.h
@@ -6,8 +6,8 @@
  * Authors:
  *     Wen Congyang <wency@cn.fujitsu.com>
  *
- * This work is licensed under the terms of the GNU GPL, version 2. See
- * the COPYING file in the top-level directory.
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
  *
  */