Blackwell support?

[EricLBuehler]

Hi @michaelfeil!

I was testing this on an SM100 machine and noticed that compilation fails here:

candle-flash-attn-v3/build.rs

Line 124 in 00f5314

assert!(compute_cap == 90, "Compute capability must be 90 (90a)");

I saw this PR upstream, and was wondering if we could similarly relax the constraint? I would be happy to add a PR for this if you would be interested.

[michaelfeil]

@EricLBuehler
The issue was that the autodetect mechanism specified cc 90 which is not the same as 90a (adds TMA descriptors).
This PR upstream is for FA2, which does not use them.

Does the underlying FA3 kernels run on Blackwell? (I am not sure) - otherwise it sounds interesting!