Issue with ROCm 6.1.2/6.2.1 spack HIP link flags

[ebchin]

Hi axom team,

I'm updating Tribol's TPLs to build with ROCm 6.1.2 and 6.2.1, and I had a few questions/issues:

1. https://github.com/LLNL/axom/blob/develop/scripts/spack/configs/toss_4_x86_64_ib_cray/spack.yaml#L163-L166: It looks like the hip subdirectory doesn't exist anymore. Should these directories be updated to e.g. /opt/rocm-6.#.#?
2. https://github.com/LLNL/axom/blob/develop/scripts/spack/packages/axom/package.py#L328: On rzvernal, this was giving the directory /opt. It looks like rocm_root = spec["hip"].prefix might give the intended directory.
3. https://github.com/LLNL/axom/blob/develop/scripts/spack/packages/axom/package.py#L358: The lib64 subdirectory doesn't exist in /opt/rocm-6.1.2 or /opt/rocm-6.2.1 (or older ROCm versions, for that matter). I think the intended directory here is lib?

When the above changes were made, the correct library paths were produced by hip_link_flags.

@chapman39