Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h
index 67c7537..016d8a0 100644
--- a/include/linux/iio/buffer-dma.h
+++ b/include/linux/iio/buffer-dma.h
@@ -1,8 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright 2013-2015 Analog Devices Inc.
  *  Author: Lars-Peter Clausen <lars@metafoo.de>
- *
- * Licensed under the GPL-2.
  */
 
 #ifndef __INDUSTRIALIO_DMA_BUFFER_H__