yolov5量化注意事项

（1）使用onnxsim ==0.4.1版本、ort版本1.13.1

 否则使用--dynamic True时所生成的onnx就会乱掉。

（2）利用trtexec生成engine

所使用的命令如下：

trtexec.exe --onnx=yolov5n_ptq_detect_dynamic.onnx --saveEngine=ptq_int8_fp16.trtmodel --int8 --fp16

 === Trace details ===
[11/28/2022-01:21:54] [I] Trace averages of 10 runs:
[11/28/2022-01:21:54] [I] Average on 10 runs - GPU latency: 10.0542 ms - Host latency: 11.208 ms (end to end 35 ms, enqueue 1.81131 ms)
[11/28/2022-01:21:54] [I] Average on 10 runs - GPU latency: 9.81727 ms - Host latency: 10.5855 ms (end to end 19.5386 ms, enqueue 1.85647 ms)
[11/28/2022-01:21:54] [I] Average on 10 runs - GPU latency: 9.69315 ms - Host latency: 10.4373 ms (end to end 19.2861 ms, enqueue