fix copy.deepcopy on LinearPackedParams (#64367)

fix copy.deepcopy on LinearPackedParams (#64367)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64367

This is the same thing as https://github.com/pytorch/pytorch/pull/56154
but for quantized linear. It fixes the behavior of `copy.deepcopy` on
these modules. Before this PR, copied instances of `LinearPackedParams`
were not properly initialized, and inspecting them raised errors of
missing `_modules`. After this PR, inspecting and using the copies
works.

Test Plan:
```
python test/test_quantization.py TestStaticQuantizedModule.test_linear_api
```

Imported from OSS

Reviewed By: jerryzh168

Differential Revision: D30702667

fbshipit-source-id: 38c26d1e72663416eeb989985b77ffc2052c12b9