[llvm] [SPIR-V] Derive FPFastMathMode from nofpclass attributes on OpenCL builtins (PR #188984)

[Juan Manuel Martinez Caamaño via llvm-commits]

https://github.com/jmmartinez commented:

Forgot to say, on my side it looks good, but wait for somebody else's approval too.

https://github.com/llvm/llvm-project/pull/188984