Revert "[ATen][CUDA][CUBLAS] cublasLtMatmul increase workspace_size (#120925)"
This reverts commit 3239f86a3df133b5977d988324639e0de7af8749.
Reverted https://github.com/pytorch/pytorch/pull/120925 on behalf of https://github.com/malfet due to Breaks internal tests, likely due to the increased memory requirements ([comment](https://github.com/pytorch/pytorch/pull/120925#issuecomment-1983875400))
