[clang] AMDGPU: Rename and add bf16 support for global_load_tr builtins (PR #86202)

[Stanislav Mekhanoshin via cfe-commits]

rampitec wrote:

> I don't think intrinsics are meant for users. Builtins are the user-facing front. :-)

Depending on who you consider an user. Are folks writing MLIR generators users?

https://github.com/llvm/llvm-project/pull/86202