!11209 [MS_LITE] add floatToint16

From: @YeFeng_24
Reviewed-by: @hangangqiang,@zhang_xue_tong
Signed-off-by: @hangangqiang

mindspore/lite/nnacl/base/cast_base.h

@@ -71,6 +71,11 @@ inline void Int32ToInt64(const int32_t *input, int64_t *output, int number) {
   }
 }
 
+inline void Float32ToInt16(const float *input, int16_t *output, int number) {
+  for (int i = 0; i < number; ++i) {
+    output[i] = (int16_t)input[i];
+  }
+}
 #ifdef __cplusplus
 }
 #endif

mindspore/lite/src/runtime/kernel/arm/fp32/cast_fp32.cc

@@ -85,6 +85,9 @@ int CastCPUKernel::DoCast(int thread_id) {
     } else if (input_data_type == kNumberTypeInt32 && output_data_type == kNumberTypeInt64) {
       Int32ToInt64(reinterpret_cast<int32_t *>(input->data_c()) + offset,
                    reinterpret_cast<int64_t *>(output_data) + offset, data_num);
+    } else if (input_data_type == kNumberTypeFloat32 && output_data_type == kNumberTypeInt16) {
+      Float32ToInt16(reinterpret_cast<float *>(input->data_c()) + offset,
+                     reinterpret_cast<int16_t *>(output_data) + offset, data_num);
     } else {
       MS_LOG(ERROR) << "Unsupported datatype from " << input_data_type << " to " << output_data_type;
       return RET_ERROR;