upgrade mkldnn-bridge (#20569)
Summary:
1. reduce the overhead of mkldnn-bridge itself
2. remove redundant code and useless APIs
3. provide new operators, including int8 inner_product, ND permute/transpose, elem_add/mul, and etc.
4. improve inner_product to support io format weights without implicit reorder
5. add SoftMax support
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20569
Reviewed By: houseroad
Differential Revision: D15558663
Pulled By: bddppq
fbshipit-source-id: 79a63aa139037924e9ffb1069f7e7f1d334efe3a
