Add missing VDSO_{NAME,HASH}_* macros and use them for PREPARE_VERSION_KNOWN

Add missing VDSO_{NAME,HASH}_* macros and use them for PREPARE_VERSION_KNOWN

Define all currently used Linux versions used for
PREPARE_VERSION{,_KNOWN} in sysdeps/unix/sysv/linux/dl-vdso.h and use
them instead of duplicating the versions and precomputed hashes across
architecture specific files.

	* sysdeps/unix/sysv/linux/aarch64/gettimeofday.c (INIT_ARCH): Use
	PREPARE_VERSION_KNOWN.
	* sysdeps/unix/sysv/linux/aarch64/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/dl-vdso.h (VDSO_NAME_LINUX_2_6_39): New
	define.
	(VDSO_HASH_LINUX_2_6_39): Likewise.
	(VDSO_NAME_LINUX_4_9): Likewise.
	(VDSO_HASH_LINUX_4_9): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/gettimeofday.c (INIT_ARCH): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/init-first.c
	(_libc_vdso_platform_setup): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/time.c (INIT_ARCH): Likewise.
	* sysdeps/unix/sysv/linux/s390/init-first.c (_libc_vdso_platform_setup):
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/init-first.c (__vdso_platform_setup):
	Likewise.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>