buildroot

mtd-utils: ubinize: fix return code on error

ubinize 1.5.2 (currently packaged in Buildroot) returns 0 in case of
some errors. This can lead to unnoticed errors in the middle of a
build.

Fix by adding a patch from upstream, which is not yet present in any
released version.

Fetch from: http://git.infradead.org/mtd-utils.git/commit/5f50207231414bfdbac8f0f974a2824f24177d6e

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>