dbr quant: support dynamic linear (#70257)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70257
Makes dynamic quantization for linear module work in DBR quant.
Coverage for more ops and functionals will be in future PRs.
Test Plan:
```
python test/test_quantization.py -k DBR
```
Reviewed By: jerryzh168
Differential Revision: D33262300
Pulled By: vkuzo
fbshipit-source-id: c1cb0f9dd3f42216ad6ba19f4222b171ff170174
