From: Sven Eckelmann <sven@narfation.org>
Date: Tue, 14 Sep 2021 21:02:10 +0200
Subject: Revert "batman-adv: Switch to kstrtox.h for kstrtou64"

This header is only available after Linux 5.14

This reverts commit c9a69cb4048ebef3a4d91835669011a26d9b7dab.

--- a/net/batman-adv/gateway_common.c
+++ b/net/batman-adv/gateway_common.c
@@ -10,7 +10,7 @@
 #include <linux/atomic.h>
 #include <linux/byteorder/generic.h>
 #include <linux/errno.h>
-#include <linux/kstrtox.h>
+#include <linux/kernel.h>
 #include <linux/limits.h>
 #include <linux/math64.h>
 #include <linux/netdevice.h>