Interfaces all have an mlink to if_$foo. Add these for the missing ones
and remove an incorrect one from rtwn_pci. Wireless network drivers are
all accessible via `apropos -s4 "wireless network driver", except two
which are "wireless network device". I actually prefer the latter, but
make them all consistent upon the more common parlance. Tag SPDX on one
of the files I touched, while here.
MFC after: 3 days