systemd-machine-units: Fix SYSTEMD_SERVICE to have _${PN} suffix

* systemd.bbclass from oe-core reads only SYSTEMD_SERVICE_
meta-android: base-files: don't export build time variables

Signed-off-by: Simon Busch <morphis@gravedo.de>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
meta-android: android-audiosystem: don't provide asound.conf

It's up to a distro layer to provide a proper asound.conf which fits its needs.

Signed-off-by: Simon Busch <morphis@gravedo.de>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>