Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/lib/extable.c b/lib/extable.c
index f54996f..c3e59ca 100644
--- a/lib/extable.c
+++ b/lib/extable.c
@@ -1,12 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Derived from arch/ppc/mm/extable.c and arch/i386/mm/extable.c.
  *
  * Copyright (C) 2004 Paul Mackerras, IBM Corp.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
  */
 
 #include <linux/bsearch.h>
@@ -14,6 +10,7 @@
 #include <linux/init.h>
 #include <linux/sort.h>
 #include <linux/uaccess.h>
+#include <linux/extable.h>
 
 #ifndef ARCH_HAS_RELATIVE_EXTABLE
 #define ex_to_insn(x)	((x)->insn)