libipw: initiate cfg80211 API conversion

Initiate the conversion of libipw to the new cfg80211 configuration API.

For now, leave CONFIG_IPW2200_PROMISCUOUS stuff alone.  Eventually
migrate it to cfg80211 when the add/del/change_virtual_intf methods
are implemented.

Signed-off-by: John W. Linville <linville@tuxdriver.com>