ROCm/HIP 6.x support

[ptheywood]

Iniitial ROCm support in #1379 is targetting ROCm >= 7.0.

A quick check to see how viable 6.x support would be:

• ROCm 6.4.2
  • Some ROCm CMake integration expects GPU_TARGETS rather than CMAKE_HIP_ARCHITECTURES (cub? hip?). Both may need to be set.
  • Crash during TestCleanup.CUDASimulation, hipErrorContextIsDestroyed context is destroyed during stream destruction
    • This is not unexpected, as (at the time of testing) I had not implemented an equivalent to flamegpu::detail::cuda::cuDevicePrimaryContextIsActive. A ROCm >= 7.0 change appears to prevent this error from occuring.
• ROCm 6.3.0
  • find_package(hip) expects AMDGPU_TARGETS rather than CMAKE_HIP_ARCHITECTURES (or GPU_TARGETS) both may need to be set
  • Had to use a physical architecture gfx942 instead of the generic gfx9-generic
• ROCm 6.2.0
  • find_package(hip) expects AMDGPU_TARGETS rather than CMAKE_HIP_ARCHITECTURES (or GPU_TARGETS) both may need to be set
  • Had to use a physical architecture gfx942 instead of the generic gfx9-generic
  • CI WError failure with 'hipFreeHost' is deprecated (although not depreacted in a later release, so probablyjust suppress this category of warning for hip <= 6.2.
• ROCm 6.1.0
  • untested