Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
index 2b5a320..bea4a75 100644
--- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c
+++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
@@ -1,8 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright 2014-2015 Analog Devices Inc.
  *  Author: Lars-Peter Clausen <lars@metafoo.de>
- *
- * Licensed under the GPL-2 or later.
  */
 
 #include <linux/slab.h>