Fix Fortran/openmp: Partial OpenMP 5.2 doacross

Fix Fortran/openmp: Partial OpenMP 5.2 doacross

This removed a checking snippet which accidentally was left in in commit
r13-2446-g938cda536019cd6a1bc0dd2346381185b420bbf8 ; this caused
fails in gfortran.dg/gomp/doacross-5.f90 (added in that very commit).
Note that a similar but refined check is now done in the middle end.
(The ME version additionally checks whether doacross is present.)

gcc/fortran/
	* openmp.cc (resolve_omp_clauses): Remove ordered/linear
	check as it is handled now in the middle end.