Update README.md

[Forchapeatl]

• Provided sample models form google drive to ease Predicting latency of saved CNN model.
• Included Example usage of command line arguements for Predicting latency of saved CNN model.
  nn-meter predict --predictor cortexA76cpu_tflite21 --predictor-version 1.0 --torchvision mnasnet mnasnet
• Included 'pip install onnx-simplifier' for torch model from torchvision model zoo (str)