[MAC80211]: remove management interface

Removes the management interface since it is only required
for hostapd/userspace MLME, will not be in the final tree
at least in this form and hostapd/userspace MLME currently
do not work against this tree anyway.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>