Do not store raw scan results

Use scan results to update the BSS table and to select the BSS for
connection, but do not store the results for longer time.

wpa_supplicant/wps_supplicant.h

@@ -21,6 +21,7 @@
 #include "wps/wps_defs.h"
 
 struct wpa_bss;
+struct wpa_scan_res;
 
 struct wps_new_ap_settings {
 	const char *ssid_hex;