Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/sound/soc/zte/zx-spdif.c b/sound/soc/zte/zx-spdif.c
index 17b6ce3..60382ec 100644
--- a/sound/soc/zte/zx-spdif.c
+++ b/sound/soc/zte/zx-spdif.c
@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2015 Linaro
  *
  * Author: Jun Nie <jun.nie@linaro.org>
- *
- * License terms: GNU General Public License (GPL) version 2
  */
 
 #include <linux/clk.h>