[clang] [clang][AMDGPU] Don't define feature macros on host code (PR #83558)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

for example, rocprim assumes warpSize is constant

https://github.com/ROCm/rocPRIM/blob/6325547d514b46d1ab51aff0195851b3fcc626d1/rocprim/include/rocprim/intrinsics/thread.hpp#L54

since device_warp_size() is used as non-type template arguments and these code are not conditioned for device compilation only.

unless rocprim is re-written, this patch will break rocprim

https://github.com/llvm/llvm-project/pull/83558