threadmanager: remove detect cpu max 16 threads for compute

[GermanAizek]

Removing restrictions greatly improves performance software rendering on multi-core systems above 16 threads.

On my 72 threads without limit, software renderer is much better to play, there is no wheezing sound, and PPSSPP also does not report that game is too slow.

In Github video sounds muted. Download video and open for listen wheezing-corrupted sounds in PPSSPP.

Before with cpu 16 threads limit:

psp_16_limit-2026-03-23_03.02.13.mp4

After:

psp_remove-2026-03-23_02.58.55.mp4

[hrydgard]

I'm surprised performance actually improved, but good that it did!

The software renderer could be a lot more efficient about how it uses multicore though, by tiling or similar approaches.

[hrydgard]

Actaully, we might want to reconsider - at least for some CPU configuration, like the ones with P cores vs E cores, as mentioned for example here: https://felixk15.github.io/posts/comment_on_parallelizing_the_physics_solver/#p--vs-e-cores

It can be a win to NOT max the number of threads on such architectures, depending on the workload.

Anyway, let's experiment with this for now..