[clang] [HIP] Don't add -fvisibility=hidden for SPIR-V compilation flow (PR #184821)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> IMHO it's better to not internalize a function during LTO than to have a non-compilable hello-world application.

CUDA / PTX didn't really accept visibility until very recently and the backend didn't have any issues. What failure are you experiencing? I'm guessing this is related to the external Khronos tools?

https://github.com/llvm/llvm-project/pull/184821