[clang] [Clang][Sema] Reject unsupported opencl address space attributes in SYCL and HLSL (PR #152528)

[Alexey Bader via cfe-commits]

https://github.com/bader commented:

This change make sense to me, but I'd like either @Fznamznon or @tahonermann to take a look as well.
My understanding is that the `opencl_generic` attribute in OpenCL has the semantics of the `Default` address space in SYCL offload mode (except for interaction with the constant address space).
Using the `opencl_generic` attribute in SYCL offload mode seems useless.

https://github.com/llvm/llvm-project/pull/152528