fix compile warning

mindspore/lite/nnacl/fp32/prelu.c

@@ -107,21 +107,18 @@ void PRelu(float *input, float *output, PReluParameter *prelu_param_, int task_i
 void PReluShareChannel(float *input, float *output, PReluParameter *prelu_param_, int task_id) {
   for (int j = task_id; j < prelu_param_->tile_block_; j += prelu_param_->op_parameter_.thread_num_) {
     int cal_index;
-    int cal_per_time;
 #ifdef ENABLE_NEON
     float32x4_t slope_value = vdupq_n_f32(prelu_param_->slope_[0]);
     float32x4_t zero_value = vdupq_n_f32(0);
 #endif
 #ifdef ENABLE_ARM64
     cal_index = j * 64;
-    cal_per_time = 64;
 
 #elif ENABLE_ARM32
     cal_index = j * 32;
-    cal_per_time = 32;
 #else
     cal_index = j * 32;
-    cal_per_time = 32;
+    int cal_per_time = 32;
 #endif
     float *input_ptr = input + cal_index;
     float *output_ptr = input + cal_index;

mindspore/lite/src/runtime/kernel/arm/fp16/cast_fp16.cc

@@ -52,7 +52,7 @@ int CastFp16CPUKernel::ReSize() {
   if (data_num_ == 0) {
     return RET_OK;
   }
-  op_parameter_->thread_num_ = MSMIN(op_parameter_->thread_num_, data_num_);
+  op_parameter_->thread_num_ = MSMIN(op_parameter_->thread_num_, static_cast<int>(data_num_));
   stride_ = UP_DIV(data_num_, op_parameter_->thread_num_);
   return RET_OK;
 }

mindspore/lite/src/runtime/kernel/arm/fp16/concat_fp16.cc

@@ -69,7 +69,7 @@ int ConcatFp16CPUKernel::MallocTmpBuffer() {
 }
 
 void ConcatFp16CPUKernel::FreeTmpBuffer() {
-  for (auto i = 0; i < fp16_inputs_.size(); i++) {
+  for (size_t i = 0; i < fp16_inputs_.size(); i++) {
     auto &in_tensor = in_tensors_.at(i);
     auto in_ptr = fp16_inputs_.at(i);
     if (in_tensor->data_type() == kNumberTypeFloat32 || in_tensor->data_type() == kNumberTypeFloat) {

mindspore/lite/src/runtime/kernel/arm/fp16/convolution_base_fp16.cc

@@ -66,7 +66,7 @@ int ConvolutionBaseFP16CPUKernel::GetExecuteFilter() {
       MS_LOG(ERROR) << "malloc fp16_weight_ failed.";
       return RET_ERROR;
     }
-    for (int i = 0; i < fp16_weight_size / sizeof(float16_t); ++i) {
+    for (size_t i = 0; i < fp16_weight_size / sizeof(float16_t); ++i) {
       fp16_weight_[i] = (float16_t)origin_weight[i];
     }
     execute_weight_ = fp16_weight_;

mindspore/lite/src/runtime/kernel/arm/fp16/reduce_fp16.cc

@@ -97,7 +97,7 @@ int ReduceFp16CPUKernel::Run() {
   }
 
   fp16_src_data_ = fp16_input_;
-  for (int i = 0; i < data_buffers_.size(); ++i) {
+  for (size_t i = 0; i < data_buffers_.size(); ++i) {
     fp16_dst_data_ = data_buffers_[i];
     outer_size_ = outer_sizes_[i];
     inner_size_ = inner_sizes_[i];