repo_missing: don't check arch recursively
Remove the recursive check, as it caused an infinite loop. It took a very long time to complete anyway, even when it worked. The reasoning for having the recursive check in the first place was, that we would have device packages with arch=noarch set in the APKBUILD, but which could only be built for a certain architecture (the device architecture). Nowadays using arch=noarch in device packages is forbidden, and we enforce that rule [1]. So the recursive arch check isn't necessary anymore.