[ao_migration] torch/nn/qat: torch.quantization -> torch.ao.quantization (#65902)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65902
This changes the imports in the `caffe2/torch/nn/qat` to include the new import locations.
```
codemod -d torch/nn/qat --extensions py 'torch.quantization' 'torch.ao.quantization'
```
Test Plan: `python test/run_test.py`
Reviewed By: jerryzh168
Differential Revision: D31301196
fbshipit-source-id: ff237790d74cd3b3b5be642a997810f4f439a1d8
