reuse already defined max instead of std numerx

[mahf708]

A pretty minor fix to suppress an annoying warning :)

min, max, etc were already defined in haero maths, so reusing them here instead of std (to special-case cuda...)

[mahf708]

cc @singhbalwinder @jeff-cohere

the warning was of the form:

.../scream/externals/haero/haero/root_finders.hpp(49): warning #20013-D: calling a constexpr __host__ function("max") from a __host__ __device__ function("NewtonSolver") is not allowed. The experimental flag '--expt-relaxed-constexpr' can be used to allow this.
          iter_diff(std::numeric_limits<Real>::max()), f(fn), fail(false) {}

[singhbalwinder]

Thanks, Naser!