fix MSVC build

[cebtenzzre]

I am attempting to get ggml to build successfully on MSVC.
This is currently a draft PR because I have not yet resolved these errors:

Resolved errors

tests\test-mul-mat2.c(1661,89): error C2440: 'type cast': cannot convert from '__m256i' to '__m256'
tests\test-mul-mat2.c(1661,28): error C2168: '_mm256_and_ps': too few actual parameters for intrinsic function
tests\test-mul-mat2.c(2049,89): error C2440: 'type cast': cannot convert from '__m256i' to '__m256'
tests\test-mul-mat2.c(2049,28): error C2168: '_mm256_and_ps': too few actual parameters for intrinsic function

I know very little about SIMD intrinsics, so I would appreciate some help with that.

edit: done.