mac80211: reorder mlme code

This reorders the mlme code a bit so we don't need all the forward
function declarations. It also removes the ERP_INFO_USE_PROTECTION
define that is unused, but otherwise contains no real changes.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>