[clang] [Clang][AMDGPU] Add builtins for instrinsic `llvm.amdgcn.raw.buffer.store` (PR #94576)

[Krzysztof Drewniak via cfe-commits]

krzysz00 wrote:

Actually, even ignoring address space 7, it feels like these builtins if you could `raw.ptr.buffer.store` any type you liked, and then they could be type-varying in Clang?

https://github.com/llvm/llvm-project/pull/94576