Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/sched_clock.h b/include/linux/sched_clock.h
index abe28d5..0bb04a9 100644
--- a/include/linux/sched_clock.h
+++ b/include/linux/sched_clock.h
@@ -1,9 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * sched_clock.h: support for extending counters to full 64-bit ns counter
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #ifndef LINUX_SCHED_CLOCK
 #define LINUX_SCHED_CLOCK