c-omp.c (c_omp_check_context_selector): Add nvidia to the list of valid vendors.

c-omp.c (c_omp_check_context_selector): Add nvidia to the list of valid vendors.

	* c-omp.c (c_omp_check_context_selector): Add nvidia to the list of
	valid vendors.

	* c-c++-common/gomp/declare-variant-3.c: Add testcase for vendor nvidia.

From-SVN: r278203