Restructure Module code [ com.android.tethering ]

Code Migration from frameworks/base/packages/Tethering ->
packages/modules/Connectivity/Tethering

BUG: 167962976
Test: m com.android.tethering + TH
Merged-In: Ib4a3a7a14d7d0e544aadf1bfb21ad390f1ba76a7
Change-Id: Ifae56d991b43c02f1e3496abbafc87d1869add8a

packages/Tethering/src/android/net/util/TetheringMessageBase.java

@@ -1,25 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * 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.
- */
-package android.net.util;
-
-/**
- * This class defines Message.what base addresses for various state machine.
- */
-public class TetheringMessageBase {
-    public static final int BASE_MAIN_SM   = 0;
-    public static final int BASE_IPSERVER = 100;
-
-}