The telit plugin is based on two main ways of checking the purpose of each port: udev tags flagging specific interfaces (with info taken from Windows .inf drivers), or otherwise using AT#PORTCFG? to query the modem about that information. If none of those applies, the port is ignored by default.

In order to support devices that are not explicitly tagged, the plugin shouldn't flag as ignored the AT-capable TTYs, instead they should be grabbed as 'secondary': ports grabbed as secondary will never be used for either primary/data IF there is another port flagged explicitly for primary/data.

This will fix support for modems with a single TTY and no explicit port type hint tag, e.g. RS232 modems with just one single TTY where there's no point in specifying port type hints: the port will be grabbed as secondary, and then automatically promoted to primary/data as there is no other port grabbed.