Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/time/timeconv.c b/kernel/time/timeconv.c
index 7142580..589e0a5 100644
--- a/kernel/time/timeconv.c
+++ b/kernel/time/timeconv.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: LGPL-2.0+
 /*
  * Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
  * This file is part of the GNU C Library.