wl12xx: AP mode - workaround for FW bug on station remove

Sometimes an event indicating station removal is not sent up by
firmware. We work around this by always indicating success in when
a wait for the event timeouts.

Temporary workaround until a FW fix is introduced.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Reviewed-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>