Enable BFloat support for gemms on arch other than ampere (#50442)
Summary:
Fixes #{issue number}
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50442
Reviewed By: bdhirsh
Differential Revision: D26044981
Pulled By: mruberry
fbshipit-source-id: 65c42f2c1de8d24e4852a1b5bd8f4b1735b2230e
