bump(sys-devel/binutils): sync with upstream

This is just a minor bump from 2.23.1 to 2.23.2 which has been stable in Gentoo for quite a long time. We need to flush versions built with the old eclass out of our system anyway so might as well do it with a version bump.

Eclass was updated here: https://github.com/coreos/portage-stable/pull/125