mt7601u: run calibration works after finishing scanning

When finishing scanning we switch to operational channel sill with
SCANNING flag. This mean that we never perform calibration works after
scanning. To fix the problem queue calibration works on
.sw_scan_complete() routine.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>