CoreNEURON does not compile with NVHPC 22.5

[olupton]

Describe the issue
As first seen in BlueBrain/spack#1606 and subsequently reported in #825, CoreNEURON does not compile with nvc++ 22.5, at least if GPU support is enabled.

This should be fixed, probably in the context of #795 which is already revisiting how global variables are handled in GPU code.

[olupton]

See also #841 (comment) for information about issues hidden behind the compilation issues.

[olupton]

I believe this was closed by #795.