Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/usb/serial/ir-usb.c b/drivers/usb/serial/ir-usb.c
index 7643716..302eb95 100644
--- a/drivers/usb/serial/ir-usb.c
+++ b/drivers/usb/serial/ir-usb.c
@@ -16,7 +16,7 @@
  * was written by Roman Weissgaerber <weissg@vienna.at>, Dag Brattli
  * <dag@brattli.net>, and Jean Tourrilhes <jt@hpl.hp.com>
  *
- * See Documentation/usb/usb-serial.txt for more information on using this
+ * See Documentation/usb/usb-serial.rst for more information on using this
  * driver
  */