[clang] [Clang][AMDGPU] Permit language address spaces for AMDGPU globals (PR #66205)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

The assertion is for preventing language-specific address space e.g. OpenCL addr space from being used in addr space agnostic languages. The numerical addr space attr are mapped to target-specific AST addr space therefore won't cause assertion.

I am OK to remove that assertion if you would like to allow using AST addr space from different languages. 

https://github.com/llvm/llvm-project/pull/66205