[libclc] [libclc] Only check the triple architecture for libclc (PR #194149)

[Michał Górny via cfe-commits]

mgorny wrote:

Thanks for the explanations. I'll limit them to `nvptx64-nvidia-cuda` and hopefully nobody will complain I broke their workflow :-).

https://github.com/llvm/llvm-project/pull/194149