[Bugfix][Kernel][Misc] Basic support for SmoothQuant, symmetric case

[rasmith]

This PR provides some basic support for the SmoothQuant model, for just the symmetric case. There was a bug in int8_quant_kernels.cu that was causing a GPU SEGV due to integer overflow. Furthermore, the rest of the kernels that support this model are all written in CUTLASS.

This PR provides a PyTorch based implementation of cutlass_scaled_mm that executes at about 17 tok/s output. At the moment, the upper bound on the runtime is 45 tok/s by basically having cutlass_scaled_mm return zero tensor.

There are improvements that could be had, but this is a start to supporting the SmoothQuant models.

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[hegemanjw4amd]

One request.

[hegemanjw4amd]

Can we factor the torch implementation out into a standalone function?

[rasmith]

Done

[hegemanjw4amd]

Seems fine for now.