Remove STA entry from AP when starting TKIP countermeasures

Remove STA entry from AP when starting TKIP countermeasures

Previously, the STA entry was removed only from the driver and the STA
entry within hostapd was just marked disassociated. However, this left
the WPA authenticator state machine with an entry and the session was
not terminated properly. In addition, the STA entry could have remaining
indefinitely if the STA did not reconnect after TKIP countermeasures.
Fix this by removing the STA entry from hostapd instead of just leaving
it disassociated.

Signed-hostap: Jouni Malinen <j@w1.fi>