Address NEMO compile warnings by WallyMaier · Pull Request #1918

Address NEMO compile warnings by WallyMaier · Pull Request #1918 · su2code/SU2

Proposed Changes

This address the issue in #1916 to resolve the Intel compiler warnings generated by NEMO.

Turns out I don't have access to an intel compiler, but -warnlevel=3 using GCC does not give any issues. @vdweide, @pcarruscag, @bigfooted could you make sure the issue is resolved?

Related Work

Issue #1916

PR Checklist

I am submitting my contribution to the develop branch.
My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).