[llvm] [SPIRV] Enable `bfloat16` arithmetic (PR #166031)

[Alex Voicu via llvm-commits]

AlexVlx wrote:

> Overall LGTM! I left a small comment regarding the testing. Thank you!

Cheers - just to clarify, are you OK with this going in as is, or would you like to add some OpFmod testing - I've commented on the thread on that, but I'm not strongly opposed to adding it if you really want it.

https://github.com/llvm/llvm-project/pull/166031