Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/iio/adc/xilinx-xadc-events.c b/drivers/iio/adc/xilinx-xadc-events.c
index dc06703..dbfd5da 100644
--- a/drivers/iio/adc/xilinx-xadc-events.c
+++ b/drivers/iio/adc/xilinx-xadc-events.c
@@ -1,10 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Xilinx XADC driver
  *
  * Copyright 2013 Analog Devices Inc.
  *  Author: Lars-Peter Clauen <lars@metafoo.de>
- *
- * Licensed under the GPL-2.
  */
 
 #include <linux/iio/events.h>