Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/clk/pistachio/clk.c b/drivers/clk/pistachio/clk.c
index 698cad4..23d076a 100644
--- a/drivers/clk/pistachio/clk.c
+++ b/drivers/clk/pistachio/clk.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2014 Google, Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
  */
 
 #include <linux/clk.h>