Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
index b1d861c..35e15df 100644
--- a/include/linux/iopoll.h
+++ b/include/linux/iopoll.h
@@ -1,15 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 and
- * only version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
  */
 
 #ifndef _LINUX_IOPOLL_H
@@ -30,7 +21,7 @@
  * @cond: Break condition (usually involving @val)
  * @sleep_us: Maximum time to sleep between reads in us (0
  *            tight-loops).  Should be less than ~20ms since usleep_range
- *            is used (see Documentation/timers/timers-howto.txt).
+ *            is used (see Documentation/timers/timers-howto.rst).
  * @timeout_us: Timeout in us, 0 means never timeout
  *
  * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
@@ -69,7 +60,7 @@
  * @cond: Break condition (usually involving @val)
  * @delay_us: Time to udelay between reads in us (0 tight-loops).  Should
  *            be less than ~10us since udelay is used (see
- *            Documentation/timers/timers-howto.txt).
+ *            Documentation/timers/timers-howto.rst).
  * @timeout_us: Timeout in us, 0 means never timeout
  *
  * Returns 0 on success and -ETIMEDOUT upon a timeout. In either