Fix a never-ending loop with multiple radios in wpa_supplicant

Commit 202dec2a94695a696236ee5a2ad1be0905ccea14 introduced a never
ending loop for a case where a single wpa_supplicant process is used
with multiple radios. Fix this by advancing the iface pointer properly
to the next interface in the loop until a NULL pointer is hit.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>

wpa_supplicant/wpa_supplicant.c

@@ -2905,6 +2905,8 @@ static struct wpa_radio * radio_add_interface(struct wpa_supplicant *wpa_s,
 			dl_list_add(&radio->ifaces, &wpa_s->radio_list);
 			return radio;
 		}
+
+		iface = iface->next;
 	}
 
 	wpa_printf(MSG_DEBUG, "Add interface %s to a new radio %s",