CMake: Enforce >= C++17 for ROCm (#3355)

## Summary

Check if this adds the C++17 flags again or if there is an undocumented
change in defaults that we need to manually address for AMD's Clang
fork'd compilers now.

## Additional background

For #3337

Tools/CMake/AMReXParallelBackends.cmake

@@ -331,6 +331,11 @@ if (AMReX_HIP)
        # ROCm 4.5: use unsafe floating point atomics, otherwise atomicAdd is much slower
        # 
        target_compile_options(amrex_${D}d PUBLIC $<$<COMPILE_LANGUAGE:CXX>:-munsafe-fp-atomics>)
+
+       # ROCm 5.5: forgets to enforce C++17 (default seems lower)
+       # https://github.com/AMReX-Codes/amrex/issues/3337
+       #
+       target_compile_options(amrex_${D}d PUBLIC $<$<COMPILE_LANGUAGE:CXX>:-std=c++17>)
    endforeach()
 
    # Equivalently, relocatable-device-code (RDC) flags are needed for `extern`