Moving cublasHgemm link to dynamic loading

[coreylowman]

Fixes #228

[coreylowman]

@jafioti I wasn't able to reproduce your error, but can you check out this branch and test with it?

I couldn't tell if you were actually trying to use those functions, but it's recommended to use the result::gemm_ex and result::gemm_strided_batched_ex for f16 gemm. Perhaps we should just remove these hgemm specific functions since they aren't included in the bindgen export. They aren't used anywhere in the safe api currently though.

[jafioti]

Sorry for the late response, this indeed does fix the issue. Thanks!