[llvm] [AMDGPU][GFX12.5] Add support for emitting memory operations with nv bit set (PR #179413)

[Pierre van Houtryve via llvm-commits]

Pierre-vh wrote:

@arsenm I pulled the metadata implementation higher in the patch stack so it doesn't affect this patch, and we can discuss it in #179415 

Do you think `MONonVolatile` is a good name ? I thought about renaming it to `MOThreadLocal` instead.
It gets weird when you have "volatile amdgpu-non-volatile" memory operands otherwise. What do you think?

https://github.com/llvm/llvm-project/pull/179413