Add Niagara-4 optimized memset/bzero implementation.

	* sysdeps/sparc/sparc64/multiarch/memset-niagara4.S: New file.
	* sysdeps/sparc/sparc32/sparcv9/multiarch/memset-niagara4.S: New
	file.
	* sysdeps/sparc/sparc64/multiarch/Makefile: Add to
	sysdep_routines.
	* sysdeps/sparc/sparc32/sparcv9/multiarch/Makefile: Likewise.
	* sysdeps/sparc/sparc64/multiarch/memset.S: Use Niagara-4 memset
	and bzero when HWCAP_SPARC_CRYPTO is present.