sys: add MBIM (mobile broadband interface module) interface type.

This is part of the upcoming USB umb(4) work.

PR: 263783
Approved by: adrian, zlei
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D48167

(cherry picked from commit 86bfbaf1002c88b5c1a6d3ed261becedb533490b)