Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/power/cpupower/lib/cpuidle.c b/tools/power/cpupower/lib/cpuidle.c
index 852d254..479c597 100644
--- a/tools/power/cpupower/lib/cpuidle.c
+++ b/tools/power/cpupower/lib/cpuidle.c
@@ -1,8 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
  *  (C) 2011       Thomas Renninger <trenn@novell.com> Novell Inc.
- *
- *  Licensed under the terms of the GNU GPL License version 2.
  */
 
 #include <stdio.h>