#37592 updated cached cmake packages to set CMAKE_CUDA_ARCHITECTURES.
The condition `if archs != "none"` lead to `CMAKE_CUDA_ARCHITECTURES=none`
when cuda_arch=none (incorrect check on the value of a multi-valued
variant), i.e. CMAKE_CUDA_ARCHITECTURES is always set. This PR udpates
the condition to if archs[0] != "none" to ensure CMAKE_CUDA_ARCHITECTURES
is only set if cuda_arch is not none (which seems to be the pattern used
in other packages).
This does the same for HIP (although in general ROCmPackage disallows
amdgpu_target=none when +rocm).
fa9fb60df3