Revert "toolchain: handle toolchains with multiple ld*.so.* files"

This breaks some existing external toolchains. Since we're very close to
a release, don't try to fix it, but instead simply revert.

This reverts commit 6f911a17.

Fixes: http://autobuild.buildroot.net/results/afe/afe44f4b6a3c53e5864cfb10b04529011e72cf5c/



Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>