selftest: add a copy of previous mtd-utils version to meta-selftest

The latest version update eliminated all custom patches, and the selftest
expects them.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
(cherry picked from commit 95298a7f)
Signed-off-by: Steve Sakoman <steve@sakoman.com>