[clang] [Clang][AMDGPU] Add a new builtin type for buffer rsrc (PR #94830)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

how does a user initialize/populate this type of objects? by calling a builtin function?

need a SemaCUDA test to make sure it is defined with  %clang_cc1 -triple x86_64-unknown-gnu-linux -aux-triple amdgcn-amd-amdhsa , like https://github.com/llvm/llvm-project/blob/main/clang/test/SemaCUDA/builtin-mangled-name.cu

https://github.com/llvm/llvm-project/pull/94830