Some devices (e173) appear to lie about NDIS support; GETPORTMODE reports NDIS
is enabled, but that port is actually the MDM port and responds to AT commands.
So, if we get a port reported as NDIS and none reported as MDM, use the one
reported as NDIS for PPP.
https://bugs.launchpad.net/ubuntu/+source/modemmanager/+bug/1057186