Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/iio/adc/ad7266.c b/drivers/iio/adc/ad7266.c
index 605eb5e..c31b8ea 100644
--- a/drivers/iio/adc/ad7266.c
+++ b/drivers/iio/adc/ad7266.c
@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * AD7266/65 SPI ADC driver
  *
  * Copyright 2012 Analog Devices Inc.
- *
- * Licensed under the GPL-2.
  */
 
 #include <linux/device.h>