At the moment, oFono/MM are usually stopped after rmtfs on shutdown.
This does not make sense, since the modem managed by oFono/MM will
disappear once rmtfs is stopped. Add a "before ofono modemmanager"
to make sure that OpenRC will stop oFono/MM before rmtfs on shutdown.
This may or may not fix some occasional hangs during shutdown,
but it definitely makes it possible for oFono/MM to shutdown cleanly.
The -s switch to automatically start/stop the modem remoteproc only
works on mainline, on downstream it fails with "Failed to get rprocfd".
Let's abuse /usr/lib/preload/libqipcrtr4msmipc.so to check if we are
(probably) running on a downstream installation, and omit the -s
argument in this case. The modem remoteproc needs to be started
differently on downstream.
qrtr-ns is not needed (or working) on downstream, also it is no longer
needed for mainline starting with Linux 5.9. Convert the "need" dependency
to a "use" so qrtr-ns is only started if it is really needed.
