mvebu: add sysupgrade support for clearfog

Add and enable sysupgrade support for clearfog boards, based on how the
brcm2708 target does it.

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Acked-by: Felix Fietkau <nbd@nbd.name>

target/linux/mvebu/base-files/lib/preinit/79_move_config

@@ -0,0 +1,18 @@
+#!/bin/sh
+# Copyright (C) 2015 OpenWrt.org
+
+BOOTPART=/dev/mmcblk0p1
+
+move_config() {
+	if [ -b $BOOTPART ]; then
+		insmod nls_cp437
+		insmod nls_iso8859-1
+		insmod fat
+		insmod vfat
+		mkdir -p /boot
+		mount -t vfat -o rw,noatime $BOOTPART /boot
+		[ -f /boot/sysupgrade.tgz ] && mv -f /boot/sysupgrade.tgz /
+	fi
+}
+
+boot_hook_add preinit_mount_root move_config