Fix inference fp16 io (#54042)

* fix trt inference fp16 io

* fix inference fp16 io

paddle/fluid/inference/tensorrt/convert/op_converter.h

@@ -359,7 +359,7 @@ class OpConverter {
           platform::errors::InvalidArgument(
               "The output tensor in TensorRT subgraph should be LoDTensor"));
       nvinfer1::DataType out_dtype = FluidDataType2TRT(var->GetDataType());
-      if (engine->WithFp16() && !engine->WithInt8() &&
+      if (engine->precision() == phi::DataType::FLOAT16 &&
           out_dtype == nvinfer1::DataType::kFLOAT &&
           engine->EnableLowPrecisionIO()) {
         out_dtype = nvinfer1::DataType::kHALF;