qtnfmac: cancel scans on wireless interface changes

Cancel active scans and deactivate firmware scan watchdog timer
when wireless interface configuration is changed. The usecases
include wireless interface mode change, interface down,
AP stop, virtual interface removal.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>