llvmpipe discarded on non-neon hw

[kwizart]

As commented in the mesa-22.2.4 rebase, there is still a need to discard the llvmpipe driver on software fallback on non-neon capable hardware.

This as shown with commit
4621b88
Without this a SIGILL is experienced when running glxgears (or glmark2).

I've tried to report at llvm that has spotted an interesting regression without fixing the SIGILL
llvm/llvm-project#59286
and reported to mesa upstream
https://gitlab.freedesktop.org/mesa/mesa/-/issues/7868

[kwizart]

Fixed with https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20766

I will re-order patches on grate-22.2 in a few...