Huawei ^NWTIME URC handling
Huawei MU709s-e emits ^NWTIME URCs which we're not handling:
ModemManager[61616]: <debug> [1573813884.840973] (ttyUSB2): <-- '<CR><LF>^NWTIME: 19/11/15,10:31:24+04,00<CR><LF>'
ModemManager[61616]: <debug> [1573813884.841179] (ttyUSB2): <-- '<CR><LF>^EONS:0<CR><LF>'
ModemManager[61616]: <debug> [1573813884.841450] (ttyUSB0): <-- '<CR><LF>^NWTIME: 19/11/15,10:31:24+04,00<CR><LF>'
ModemManager[61616]: <debug> [1573813884.841539] (ttyUSB0): <-- '<CR><LF>^EONS:0<CR><LF>'
ModemManager[61616]: <debug> [1573813884.925014] (ttyUSB0): <-- '<CR><LF>^NDISSTAT: 0,33,,"IPV4"<CR><LF>'