[hotfix] fix misleadingly summary BLAS=MKL when there's no BLAS install (#47803)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/47803
Reviewed By: samestep
Differential Revision: D24907453
Pulled By: walterddr
fbshipit-source-id: a3e41041f6aa506b054eb0ffc61f8525ba02cbf1
