nvptx: Support '-march=sm_37'

nvptx: Support '-march=sm_37'

	gcc/
	* config/nvptx/nvptx-sm.def: Add '37'.
	* config/nvptx/nvptx-gen.h: Regenerate.
	* config/nvptx/nvptx-gen.opt: Likewise.
	* config/nvptx/nvptx.cc (first_ptx_version_supporting_sm): Adjust.
	* config/nvptx/nvptx.opt (-march-map=sm_37, -march-map=sm_50):
	Likewise.
	* config.gcc: Likewise.
	* doc/invoke.texi (Nvidia PTX Options): Document '-march=sm_37'.
	* config/nvptx/gen-multilib-matches-tests: Extend.
	gcc/testsuite/
	* gcc.target/nvptx/march-map=sm_37.c: Adjust.
	* gcc.target/nvptx/march-map=sm_50.c: Likewise.
	* gcc.target/nvptx/march-map=sm_52.c: Likewise.
	* gcc.target/nvptx/march=sm_37.c: New.
	libgomp/
	* testsuite/libgomp.c/declare-variant-3-sm37.c: New.
	* testsuite/libgomp.c/declare-variant-3.h: Adjust.