Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/iio/proximity/srf08.c b/drivers/iio/proximity/srf08.c
index f2bf783..b23ce44 100644
--- a/drivers/iio/proximity/srf08.c
+++ b/drivers/iio/proximity/srf08.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * srf08.c - Support for Devantech SRFxx ultrasonic ranger
  *           with i2c interface
@@ -5,10 +6,6 @@
  *
  * Copyright (c) 2016, 2017 Andreas Klinger <ak@it-klinger.de>
  *
- * This file is subject to the terms and conditions of version 2 of
- * the GNU General Public License. See the file COPYING in the main
- * directory of this archive for more details.
- *
  * For details about the device see:
  * http://www.robot-electronics.co.uk/htm/srf08tech.html
  * http://www.robot-electronics.co.uk/htm/srf10tech.htm