In the config() callback function the fields radio_enabled and
the change flag IEEE80211_CONF_CHANGE_RADIO_ENABLED have been
deprecated. This removes the usage of those fields by improving
antenna change detection in the antenna configuration function.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>