if_wi driver

["Angelos D. Keromytis" <angelos_(_at_)_keromytis_(_dot_)_org>]

Unless I hear objections in the next week or so, I'll be changing the default
mode in the wi driver from ad-hoc to BSS. There has recently been a discussion
at one of the netbsd mailing lists about this; to summarize:

1) BSS is an IEEE standard, the ad-hoc mode is not.
2) The latest firmware revisions support *2* kinds of ad-hoc mode.
3) Most large installations use BSS mode anyway.

-Angelos