cleanup the RAID6 P/Q library v3

[H. Peter Anvin]

On 2026-05-19 01:24, Christoph Hellwig wrote:
> 
> raid6: rework registration of optimized algorithms
> 
>  - avx2 instead of avx512 is probably the right thing for no
>    benchmarking, but if it was intentional (it wasn't), that should
>    be document.  So I'll just switch back to the previous version to
>    keep the state of the art

It is unlikely to be the right thing *going forward*, though.

The very unfortunate performance inversion is likely model-specific. It is one
of those things where you largely would have to have a list of quirks :(

	-hpa