Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/pm_clock.h b/include/linux/pm_clock.h
index 09779b0..8ddc786 100644
--- a/include/linux/pm_clock.h
+++ b/include/linux/pm_clock.h
@@ -1,9 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * pm_clock.h - Definitions and headers related to device clocks.
  *
  * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
- *
- * This file is released under the GPLv2.
  */
 
 #ifndef _LINUX_PM_CLOCK_H