Don't duplicate in the Fortran front end what's generically being checked in
the middle end.

	gcc/fortran/
	* openmp.c (resolve_oacc_loop_blocks): Remove checking of OpenACC
	loop clauses.
	gcc/testsuite/
	* gfortran.dg/goacc/loop-2-kernels.f95: Update.
	* gfortran.dg/goacc/loop-2-parallel.f95: Likewise.
	* gfortran.dg/goacc/nested-parallelism.f90: Likewise.

From-SVN: r266922