powerpc: Add hwcap/hwcap2/platform data to TCB.

powerpc: Add hwcap/hwcap2/platform data to TCB.

This patch adds a new feature for powerpc.  In order to get faster access to
the HWCAP/HWCAP2 bits and platform number (i.e. for implementing
__builtin_cpu_is () / __builtin_cpu_supports () in GCC) without the overhead of
reading from the auxiliary vector, we now reserve space for them in the TCB.
This is an ABI change for GLIBC 2.23.

A new versioned symbol '__parse_hwcap_and_convert_at_platform' is available to
get the data from the auxiliary vector and parse it, and store it for later use
in the TLS initialization code.  This function is called very early
(in _dl_sysdep_start () via DL_PLATFORM_INFO for the dynamic linking case, and
in __libc_start_main () for the static linking case) to make sure the data is
available at the time of TLS initialization.

	* sysdeps/powerpc/Makefile (sysdep-dl-routines): Add hwcapinfo.
	(sysdep_routines): Likewise.
	(sysdep-rtld-routines): Likewise.
	[$(subdir) = nptl](tests): Add test-get_hwcap and test-get_hwcap-static
	[$(subdir) = nptl](tests-static): test-get_hwcap-static
	* sysdeps/powerpc/Versions: Added new
	__parse_hwcap_and_convert_at_platform symbol to GLIBC-2.23.
	* sysdeps/powerpc/hwcapinfo.c: New file.
	(__tcb_parse_hwcap_and_convert_at_platform): New function to initialize
	and parse hwcap, hwcap2 and platform number information.
	* sysdeps/powerpc/hwcapinfo.h: New file.  Creates global variables
	to store HWCAP+HWCAP2 and platform number.
	* sysdeps/powerpc/nptl/tcb-offsets.sym: Added new offsets
	for HWCAP+HWCAP2 and platform number in the TCB.
	* sysdeps/powerpc/nptl/tls.h: New functionality.  Stores
	the HWCAP, HWCAP2 and platform number in the TCB.
	(dtv): Added new fields for HWCAP+HWCAP2 and platform number.
	(TLS_INIT_TP): Included calls to add the hwcap and
	at_platform values in the TCB in TP initialization.
	(TLS_DEFINE_INIT_TP): Likewise.
	(THREAD_GET_HWCAP): New macro.
	(THREAD_SET_HWCAP): Likewise.
	(THREAD_GET_AT_PLATFORM): Likewise.
	(THREAD_SET_AT_PLATFORM): Likewise.
	* sysdeps/powerpc/powerpc32/dl-machine.h:
	(dl_platform_init): New function that calls
	__parse_hwcap_and_convert_at_platform for the dymanic linking case for
	powerpc32.
	* sysdeps/powerpc/powerpc64/dl-machine.h: Likewise, for powerpc64.
	* sysdeps/powerpc/test-get_hwcap-static.c: New file.  Testcase for
	this functionality, static linking case.
	* sysdeps/powerpc/test-get_hwcap.c: New file.  Likewise, dynamic
	linking case.
	* sysdeps/unix/sysv/linux/powerpc/libc-start.c: Added call to
	__parse_hwcap_and_convert_at_platform for the static linking case.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/ld.abilist:
	Included the new __parse_hwcap_and_convert_at_platform symbol in the
	ABI list for GLIBC 2.23.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/ld-le.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/ld.abilist:
	Likewise.