[MQTT] Simplifies MQTT CMakeLists file

- Uses mocks from tools instead of creating them.
- Move host based definition to test code.

components/tcp_transport/include/esp_transport_tcp.h

@@ -1,22 +1,15 @@
-// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #ifndef _ESP_TRANSPORT_TCP_H_
 #define _ESP_TRANSPORT_TCP_H_
 
 #include "esp_transport.h"
 #include <sys/socket.h>
+#include <net/if.h>
 
 #ifdef __cplusplus
 extern "C" {