Use status code 17 (unable to handle new STA) on max-STA limitation

This is more useful information than the previously used value 1
(unspecified failure).

Signed-hostap: Ben Greear <greearb@candelatech.com>

src/ap/drv_callbacks.c

@@ -469,7 +469,7 @@ static void hostapd_notif_auth(struct hostapd_data *hapd,
 	if (!sta) {
 		sta = ap_sta_add(hapd, rx_auth->peer);
 		if (sta == NULL) {
-			status = WLAN_STATUS_UNSPECIFIED_FAILURE;
+			status = WLAN_STATUS_AP_UNABLE_TO_HANDLE_NEW_STA;
 			goto fail;
 		}
 	}

src/ap/ieee802_11.c

@@ -645,7 +645,7 @@ static void handle_auth(struct hostapd_data *hapd,
 
 	sta = ap_sta_add(hapd, mgmt->sa);
 	if (!sta) {
-		resp = WLAN_STATUS_UNSPECIFIED_FAILURE;
+		resp = WLAN_STATUS_AP_UNABLE_TO_HANDLE_NEW_STA;
 		goto fail;
 	}