If a device reports that qmi-pdc is supported (e.g. DW5821e that
supports both fastboot and qmi-pdc), we'll end up first running the
fastboot installation before doing the qmi-pdc installation procedure.
These changes also make sure that the MM device inhibition is kept for
as long as the whole process is ongoing. Only after the last method is
run, the inhibition will be removed.
In order to handle devices being exposed in the system while the MM
inhibition is in place, e.g. to be able to run qmi-pdc after fastboot,
a simple udev based watcher is included, which will take care of
creating the FuMmDevice that is not associated to any modem currently
exposed by MM, but that shares all the details of the original device.
This new logic assumes that the devices don't change their USB layout
during a firmware upgrade, which is not a very good assumption, but it
works for the case at hand. If this is not the case, we may need to
end up doing some custom AT port probing instead of relying on the
original one reported by MM being still valid (note that we don't rely
on the device name, as that may change if some other device is plugged
in the system while we're doing the update, we rely on the USB
interface number).
