Sync from tflite-micro. (#182)

Author: TFLM-bot

src/tensorflow/lite/micro/kernels/micro_ops.h

@@ -109,6 +109,7 @@ TfLiteRegistration Register_STRIDED_SLICE();
 TfLiteRegistration Register_SUB();
 TfLiteRegistration Register_SUM();
 TfLiteRegistration Register_SVDF();
+TfLiteRegistration Register_TANH();
 TfLiteRegistration Register_TRANSPOSE();
 TfLiteRegistration Register_TRANSPOSE_CONV();
 // TODO(b/230666079): resolve conflict with xtensa implementation
@@ -132,8 +133,6 @@ TfLiteRegistration Register_SIN();
 TfLiteRegistration Register_SQRT();
 TfLiteRegistration Register_SQUARE();
 TfLiteRegistration Register_L2_NORMALIZATION();
-TfLiteRegistration Register_TANH();
-
 }  // namespace micro
 }  // namespace ops
 }  // namespace tflite

src/tensorflow/lite/micro/kernels/tanh.cpp

@@ -1,4 +1,4 @@
-/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+/* Copyright 2023 The TensorFlow Authors. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -28,10 +28,9 @@ limitations under the License.
 #include "tensorflow/lite/micro/micro_utils.h"
 
 namespace tflite {
-namespace ops {
-namespace micro {
-namespace activations {
+
 namespace {
+
 constexpr int kInputTensor = 0;
 constexpr int kOutputTensor = 0;
 
@@ -148,8 +147,6 @@ TfLiteStatus TanhPrepare(TfLiteContext* context, TfLiteNode* node) {
   return kTfLiteOk;
 }
 
-}  // namespace
-
 TfLiteStatus TanhEval(TfLiteContext* context, TfLiteNode* node) {
   const TfLiteEvalTensor* input =
       tflite::micro::GetEvalInput(context, node, kInputTensor);
@@ -193,12 +190,10 @@ TfLiteStatus TanhEval(TfLiteContext* context, TfLiteNode* node) {
   }
 }
 
-}  // namespace activations
+}  // namespace
 
 TfLiteRegistration Register_TANH() {
-  return tflite::micro::RegisterOp(
-      activations::TanhInit, activations::TanhPrepare, activations::TanhEval);
+  return tflite::micro::RegisterOp(TanhInit, TanhPrepare, TanhEval);
 }
-}  // namespace micro
-}  // namespace ops
+
 }  // namespace tflite

src/tensorflow/lite/micro/micro_mutable_op_resolver.h

@@ -539,8 +539,7 @@ class MicroMutableOpResolver : public MicroOpResolver {
   }
 
   TfLiteStatus AddTanh() {
-    return AddBuiltin(BuiltinOperator_TANH, tflite::ops::micro::Register_TANH(),
-                      ParseTanh);
+    return AddBuiltin(BuiltinOperator_TANH, Register_TANH(), ParseTanh);
   }
 
   TfLiteStatus AddTransposeConv() {