mtd-utils: upgrade 2.1.2 -> 2.1.3

Drop also --enable-install-tests from configuration options because this
was removed in 2.1.3.

(cherry picked from commit c95c852b)
Signed-off-by: Stefano Babic <sbabic@denx.de>
CC: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
CC: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>