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

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> So there is no reason to build three different nvidia triples that were on the list before?
> 
> ```
> nvptx64--
> nvptx64--nvidiacl
> nvptx64-nvidia-cuda
> ```

Probably changes the ABI slightly but that usually only matters on kernel barriers. I don't think nvidiacl was ever really supported much in the first place.

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