[libclc] [libclc] Canonicalize 'clspv' to the 'spirv-unknown-vulkan' triple (PR #196351)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> Here is the change I have to make it work on my side

Applied, thanks. I neglected to realize that plain `spirv` is not 32-bit like it is in most other targets.

https://github.com/llvm/llvm-project/pull/196351