Add interface name to some debug prints

This makes it easier to figure out what is happening when controlling
multiple interfaces from a single wpa_supplicant process.

wpa_supplicant/events.c

@@ -885,7 +885,7 @@ static void wpa_supplicant_event_scan_results(struct wpa_supplicant *wpa_s,
 		return;
 	}
 
-	wpa_printf(MSG_DEBUG, "New scan results available");
+	wpa_printf(MSG_DEBUG, "%s: New scan results available", wpa_s->ifname);
 	wpa_msg_ctrl(wpa_s, MSG_INFO, WPA_EVENT_SCAN_RESULTS);
 	wpas_notify_scan_results(wpa_s);
 

wpa_supplicant/wpa_supplicant.c

@@ -533,8 +533,8 @@ void wpa_supplicant_set_state(struct wpa_supplicant *wpa_s,
 {
 	enum wpa_states old_state = wpa_s->wpa_state;
 
-	wpa_printf(MSG_DEBUG, "State: %s -> %s",
-		   wpa_supplicant_state_txt(wpa_s->wpa_state),
+	wpa_printf(MSG_DEBUG, "%s: State: %s -> %s",
+		   wpa_s->ifname, wpa_supplicant_state_txt(wpa_s->wpa_state),
 		   wpa_supplicant_state_txt(state));
 
 	if (state != WPA_SCANNING)