[clang] [AMDGPU] Correctly determine the toolchain linker (PR #89803)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

Note that this doesn't affect OpenMP or HIP. The former uses the `clang-linker-wrapper` while the latter calls `lld` directly.

https://github.com/llvm/llvm-project/pull/89803