[PATCH] aarch64: Improve codegen of AdvSIMD logf function family

[Wilco Dijkstra]

Hi Joana,

> Load the polynomial evaluation coefficients into 2 vectors and use lanewise MLAs.
> 8% improvement in throughput microbenchmark on Neoverse V1 for log2 and log;
> 2% improvement in throughput microbenchmarkon Neoverse V1 for log10.

OK - pushed (needed an extra return at the end).

Cheers,
Wilco