cfg80211 is now *the* wireless configuration API. Lets also
give a little explanation as to what it is and refer people to
the wireless wiki for more information.

Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>