Fix AP mode wps_pin command to return the entered PIN

This command is supposed to return the PIN value that was generated
or passed in as an argument. In the AP case, the entered PIN was not
being returned.

wpa_supplicant/ap.c

@@ -481,7 +481,8 @@ int wpa_supplicant_ap_wps_pin(struct wpa_supplicant *wpa_s, const u8 *bssid,
 		unsigned int rpin = wps_generate_pin();
 		ret_len = os_snprintf(buf, buflen, "%d", rpin);
 		pin = buf;
-	}
+	} else
+		ret_len = os_snprintf(buf, buflen, "%s", pin);
 
 	ret = hostapd_wps_add_pin(wpa_s->ap_iface->bss[0], bssid, "any", pin,
 				  0);