Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/sh/mm/cache-sh2a.c b/arch/sh/mm/cache-sh2a.c
index ee87d08..4f7739e 100644
--- a/arch/sh/mm/cache-sh2a.c
+++ b/arch/sh/mm/cache-sh2a.c
@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * arch/sh/mm/cache-sh2a.c
  *
  * Copyright (C) 2008 Yoshinori Sato
- *
- * Released under the terms of the GNU GPL v2.0.
  */
 
 #include <linux/init.h>