[clang] [HIP] Default to COV5 for HIP compilations (PR #116077)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> Hmm, I thought this is already the default one if nothing is specified

My thoughts as well, but apparently not. Something else no one ever upstreamed from the AMD fork.

https://github.com/llvm/llvm-project/pull/116077