wifi: mac80211: fix double SW scan stop

When we stop a not-yet-started scan, we erroneously call
into the driver, causing a sequence of sw_scan_start()
followed by sw_scan_complete() twice. This will cause a
warning in hwsim with next in line commit that validates
the address passed to wmediumd/virtio. Fix this by doing
the calls only if we were actually scanning.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/scan.c

@@ -482,7 +482,7 @@ static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 	/* Set power back to normal operating levels. */
 	ieee80211_hw_config(local, 0);
 
-	if (!hw_scan) {
+	if (!hw_scan && was_scanning) {
 		ieee80211_configure_filter(local);
 		drv_sw_scan_complete(local, scan_sdata);
 		ieee80211_offchannel_return(local);