[flang] Fix warning fix

This fixes 73c646a.

I misread the #ifdefs and didn't realise that they were in
the middle of passing parameters to a function.

Move the workaround outside this.

Author: DavidSpickett

flang/lib/Evaluate/fold-integer.cpp

@@ -704,6 +704,7 @@ Expr<Type<TypeCategory::Integer, KIND>> FoldIntrinsicFunction(
         return common::visit(
             [&funcRef, &context, &FromInt64](const auto &str) -> Expr<T> {
               using Char = typename std::decay_t<decltype(str)>::Result;
+              (void)FromInt64;
               return FoldElementalIntrinsic<T, Char>(context,
                   std::move(funcRef),
                   ScalarFunc<T, Char>(
@@ -719,7 +720,6 @@ Expr<Type<TypeCategory::Integer, KIND>> FoldIntrinsicFunction(
       // CharacterUtils<2>::ICHAR(). Can't find a work-around,
       // so remove the FromInt64 error checking lambda that
       // seems to have caused the proble.
-                      (void)FromInt64;
                       [](const Scalar<Char> &c) {
                         return CharacterUtils<Char::kind>::ICHAR(
                             CharacterUtils<Char::kind>::Resize(c, 1));