For those who don't care about the QMI support through libqmi-glib, or if you're
stuck with glib 2.30 (libqmi-glib requires 2.32), this configure switch allows
disabling the QMI support completely.
The logic to detect cdc-wdm ports is still in place, but the QMI probing is
never launched at them. Also, all QMI-related objects won't be compiled.
Different ports of the same modem may get handled by different drivers. We
therefore need to provide a list of drivers (new `Modem.Drivers' property with
signature 'as') instead of just one (removed `Modem.Driver' property with
signature 's').
$ sudo mmcli -m 0 | grep drivers
| drivers: 'qcserial, qmi_wwan'
