wlcore: don't stop sched_scan on interface removal

Stopping sched scan on interface removal (during recovery)
is no longer needed, as sched scanning is automatically
restarted by mac80211.

Signed-off-by: Barak Bercovitz <barak@wizery.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>