Add possibility of running HPL-MxP

[geerlingguy]

I was at the Top500 BoF today at SC25, and noticed they are giving a little more attention to non-FP64 benchmarks like MxP (Mixed Precision), since a lot of 'AI' infrastructure, especially, doesn't require the same precision as scientific research and long-term data modeling.

It would be nice to be able to run the MxP test instead of only the standard FP64 HPL benchmark with this same playbook (maybe with a configuration option for which benchmarks to run).

See: https://hpl-mxp.org/rules.md

[geerlingguy]

From Nvidia, for x86/Arm: https://docs.nvidia.com/nvidia-hpc-benchmarks/HPL_MxP_benchmark.html

And from AMD: https://www.amd.com/en/developer/zen-software-studio/applications/pre-built-applications.html

Hmm... looks like outside of those two implementations, there's only the reference implementation, which is not necessarily optimized for all architectures: https://hpl-mxp.org/software.md