[nvptx] Unify C/Fortran routine handling in nvptx_goacc_validate_dims

[nvptx] Unify C/Fortran routine handling in nvptx_goacc_validate_dims

The Fortran front-end has a bug (PR72741) that means what when
nvptx_goacc_validate_dims is called for a Fortran routine, the dims parameter
is not the same as it would have been if the function would have been called for
an equivalent C routine.

Work around this bug by overriding the dims parameter for routines, allowing the
function to handle routines in Fortran and C the same.

Build and reg-tested on x86_64 with nvptx accelerator.

2018-12-17  Tom de Vries  <tdevries@suse.de>

	* config/nvptx/nvptx.c (nvptx_goacc_validate_dims): Work around Fortran
	bug PR72741 by overriding dims parameter for routines.

From-SVN: r267213