Parametrize some define_insn to simplify code in define_expands generating
those insns.

Build and reg-tested on x86_64 with nvptx accelerator.

2019-06-18  Tom de Vries  <tdevries@suse.de>

	* config/nvptx/nvptx-protos.h (gen_set_softstack_insn): Remove.
	* config/nvptx/nvptx.c (gen_set_softstack_insn): Remove.
	* config/nvptx/nvptx.md (define_insn "set_softstack_<mode>"): Rename to ...
	(define_insn "@set_softstack_<mode>"): ... this.
	(define_insn "omp_simt_enter_<mode>"): Rename to ...
	(define_insn "@omp_simt_enter_<mode>"): ... this.
	(define_insn "omp_simt_exit_<mode>"): Rename to ...
	(define_insn "@omp_simt_exit_<mode>"): ... this.

From-SVN: r272413