move mm_cpu from BlasWrappersCPU.cpp to LinearAlgebra.cpp and delete the former file (#39700)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39700
Refactored files
1. Moved mm_cpu from BlasWrappersCPU.cpp to LinearAlgebra.cpp
2. Deleted BlasWrappersCPU.cpp
These functions are closely related to those in LinearAlgebra.cpp, we don't need a seperate file.
ghstack-source-id: 105503249
Test Plan:
`buck build //caffe2/aten/...`
`buck build //xplat/caffe2:ptmobile_benchmarkAndroid#android-armv7`
CI
Reviewed By: dreiss
Differential Revision: D21692154
fbshipit-source-id: 4edb7cee53c9e29700372f16ca1e6f85539dac24
