wlcore: don't call ieee80211_sched_scan_stopped directly

When we stop sched scan during connection, we shouldn't
call ieee80211_sched_scan_stopped directly, but do it
in the normal flow, as part of the SCHED_SCAN_COMPLETED
event handling.

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>