Fix type checking errors in fx/utils.py (#66311)
Summary:
- [x] Fix the Pyre type checking errors in `torch/quantization/fx/utils.py`
```
torch/quantization/fx/utils.py:490:4 Incompatible variable type [9]: target_module_type is declared to have type `Type[nn.modules.module.Module]` but is used as type `None`.
```
Fixes the issue: [MLH-Fellowship/pyre-check/issues/75](https://github.com/MLH-Fellowship/pyre-check/issues/75)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66311
Reviewed By: pradeep90
Differential Revision: D31506399
Pulled By: 0xedward
fbshipit-source-id: 3d866fba6005452378d4a2613b8689fa2d7a8b67
