mtd-utils: revert faulty upstream patch for now

mtd-utils: revert faulty upstream patch for now

Some of the ubi-tools in the upstream mtd-utils have been
broken by a bad patch upstream. It causes major breakage
during sysupgrade when the kernel, rootfs, ... volumes
are deleted in the wrong order.

This patch therefore reverts the faulty upstream commit which
fixes the bug.

linux-mtd mailing-list thread:
<http://lists.infradead.org/pipermail/linux-mtd/2018-June/081562.html>

Cc: John Crispin <john@phrozen.org>
Reported-by: L. Wayne Leach <LLeachii@aol.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>