- Add a central child_wlans function to return the list of wlans for a wireless NIC and replace various calls to fetch the wlans_IF variable to invoke this wrapper function instead.
- If wlans_IF is not set, use a default value that creates a single wlan matching the NIC's name.
The end result of this is that each wireless NIC will now have a single
wlan interface whose name matches the NIC (e.g. iwn0) out of the box.
Existing configurations will continue to work, but this probably means we
can remove special case logic from the installer to handle wireless NICs,
etc. Users who wish to use multiple wlan devices for a single NIC can
still do so using the existing framework, but the common case of a single
client wlan will more closely match the experience of other NICs in
FreeBSD (e.g. just setting ifconfig_iwn0="WPA DHCP" in rc.conf).