more accurate omp in fortran

[Dominique d'Humières]

> diff --git a/gcc/fortran/openmp.c b/gcc/fortran/openmp.c

Revision r229609 breaks bootstrap:

../../work/gcc/fortran/openmp.c: In function 'void resolve_omp_clauses(gfc_code*, gfc_omp_clauses*, gfc_namespace*, bool)':
../../work/gcc/fortran/openmp.c:2925:27: error: format '%L' expects argument of type 'locus*', but argument 3 has type 'locus' [-Werror=format=]
     n->sym->name, n->where);
                           ^
cc1plus: all warnings being treated as errors

TIA

Dominique