tests: Wait for scan to complete on all interfaces in reset()

tests: Wait for scan to complete on all interfaces in reset()

When WpaSupplicant executes reset() it waits until all the ongoing scans
are completed. However, it checks the status of the wlanX interface
only. If a dedicated P2P device interface is used, scan may be still
running on the P2P Device interface, e.g., due to P2P_FIND. This might
affect subsequent tests.

Fix this by waiting until the scan is done both on wlanX and P2P
Device interfaces.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>