ipq40xx: Create /var/lock directory in platform_do_upgrade_*

The sysupgrade_pre_upgrade hook was removed with 5e1b4c57de ("base-files:
drop fwtool_pre_upgrade") while there were still scripts using it:

* target/linux/ar71xx/base-files/lib/upgrade/allnet.sh
* target/linux/ar71xx/base-files/lib/upgrade/openmesh.sh
* target/linux/ipq40xx/base-files/lib/upgrade/openmesh.sh

Not running the hooks can either prevent a successful upgrade or brick the
device because the fw_setenv program cannot be started correctly.

Instead of adding this hook again, the directory /var/lock for fw_setenv
can also just be created directly before fw_setenv is called.

Fixes: 5e1b4c57de ("base-files: drop fwtool_pre_upgrade")
Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>

target/linux/ipq40xx/base-files/lib/upgrade/openmesh.sh

@@ -98,16 +98,9 @@ platform_do_upgrade_openmesh() {
 	printf "rootfs_checksum %s\n" ${rootfs_md5} >> $setenv_script
 
 	# store u-boot env changes
+	mkdir -p /var/lock
 	fw_setenv -s $setenv_script || {
 		echo "failed to update U-Boot environment"
 		return 1
 	}
 }
-
-# create /var/lock for the lock "fw_setenv.lock" of fw_setenv
-# the rest is copied using ipq806x's RAMFS_COPY_BIN and RAMFS_COPY_DATA
-platform_add_ramfs_ubootenv()
-{
-	mkdir -p $RAM_ROOT/var/lock
-}
-append sysupgrade_pre_upgrade platform_add_ramfs_ubootenv