Prefer MBIM over AT on a dongle that supports both

[Ben Chan]

The ZTE MF193M dongle has both MBIM and AT port. I found that
ModemManager sometimes picked MBIM as the primary port (i.e. the
generic plugin is used), and sometimes picked AT (i.e. the zte plugin
is used). I guess the selection depends on the port probing order.
Other than blacklisting the AT port, is there a way to prefer MBIM
over AT?

Ben