Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/arm/kernel/entry-v7m.S b/arch/arm/kernel/entry-v7m.S
index abcf478..de1f206 100644
--- a/arch/arm/kernel/entry-v7m.S
+++ b/arch/arm/kernel/entry-v7m.S
@@ -1,12 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * linux/arch/arm/kernel/entry-v7m.S
  *
  * Copyright (C) 2008 ARM Ltd.
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  * Low-level vector interface routines for the ARMv7-M architecture
  */
 #include <asm/memory.h>
@@ -146,3 +143,7 @@
 	.rept	CONFIG_CPU_V7M_NUM_IRQ
 	.long	__irq_entry		@ External Interrupts
 	.endr
+	.align	2
+	.globl	exc_ret
+exc_ret:
+	.space	4