pytorch

74375299 - add torch.nn._intrinsic and torch.nn._intrinsic.quantized namespace (#20940)

add torch.nn._intrinsic and torch.nn._intrinsic.quantized namespace (#20940) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/20940 - `torch.nn._intrinsic` will contain normal(unquantized) fused modules like Conv2DRelu, Conv2DBnRelu, FakeQuantize ops etc. - `torch.nn._intrinsic` will contain fused and quantized modules like Quantized Conv2DRelu, Quantized LinearRelu etc. Right now I only added FakeQuantize op in `torch.nn._intrinsic` namespace, we'll have more later Differential Revision: D15505228 fbshipit-source-id: d380929e38af7a5bcfbea27474d5b80f95d43b03