Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/uapi/linux/aio_abi.h b/include/uapi/linux/aio_abi.h
index ce43d34..8387e0a 100644
--- a/include/uapi/linux/aio_abi.h
+++ b/include/uapi/linux/aio_abi.h
@@ -50,6 +50,8 @@
  *
  * IOCB_FLAG_RESFD - Set if the "aio_resfd" member of the "struct iocb"
  *                   is valid.
+ * IOCB_FLAG_IOPRIO - Set if the "aio_reqprio" member of the "struct iocb"
+ *                    is valid.
  */
 #define IOCB_FLAG_RESFD		(1 << 0)
 #define IOCB_FLAG_IOPRIO	(1 << 1)