broadband-modem-qmi|mbim: allow limiting multiplexed links with udev tags
Certain QMI or MBIM devices may not be able to support multiplexing at all, or they may support a limited amount of links.
The new ID_MM_MAX_MULTIPLEXED_LINKS udev tag allows specifying the maximum number of supported multiplexed links; e.g. 0 to report none supported or 1 to report that one single multiplexed link is supported.