Summary:
X-link: https://github.com/facebookresearch/FBGEMM/pull/1081

Pull Request resolved: https://github.com/pytorch/FBGEMM/pull/3997

Update README for FBGEMM GenAI kernels.

Reviewed By: q10, jiawenliu64

Differential Revision: D73325207

fbshipit-source-id: 19bb528ca98452a8126460c7c3a347dcbdf8849b