broadband-modem: don't assert if no AT port in QMI modem enabling unsolicited messages
2023-09-11T20:23:49.294555Z mm_port_get_device: assertion 'self != NULL' failed 2023-09-11T20:23:49.294691Z [modem0] enabling messaging unsolicited events on primary port (null) 2023-09-11T20:23:49.294865Z [modem0] enabling parent messaging unsolicited events failed: Cannot run sequence: port not given