Add model phlippe_densenet (#1325)
Summary:
add model [phlippe_densenet](https://github.com/phlippe/uvadlc_notebooks_benchmarking/blob/main/PyTorch/Tutorial5_Inception_ResNet_DenseNet.py)
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1325
Reviewed By: davidberard98
Differential Revision: D41896360
Pulled By: xuzhao9
fbshipit-source-id: f575287049917ef35a4288d28bd016af5ec8ad98
