Refactor hp-timing rtld usage

Refactor hp-timing rtld usage

This patch refactor how hp-timing is used on loader code for statistics
report.  The HP_TIMING_AVAIL and HP_SMALL_TIMING_AVAIL are removed and
HP_TIMING_INLINE is used instead to check for hp-timing avaliability.
For alpha, which only defines HP_SMALL_TIMING_AVAIL, the HP_TIMING_INLINE
is set iff for IS_IN(rtld).

Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu. I also
checked the builds for all afected ABIs.

	* benchtests/bench-timing.h: Replace HP_TIMING_AVAIL with
	HP_TIMING_INLINE.
	* nptl/descr.h: Likewise.
	* elf/rtld.c (RLTD_TIMING_DECLARE, RTLD_TIMING_NOW, RTLD_TIMING_DIFF,
	RTLD_TIMING_ACCUM_NT, RTLD_TIMING_SET): Define.
	(dl_start_final_info, _dl_start_final, dl_main, print_statistics):
	Abstract hp-timing usage with RTLD_* macros.
	* sysdeps/alpha/hp-timing.h (HP_TIMING_INLINE): Define iff IS_IN(rtld).
	(HP_TIMING_AVAIL, HP_SMALL_TIMING_AVAIL): Remove.
	* sysdeps/generic/hp-timing.h (HP_TIMING_AVAIL, HP_SMALL_TIMING_AVAIL,
	HP_TIMING_NONAVAIL): Likewise.
	* sysdeps/ia64/hp-timing.h (HP_TIMING_AVAIL, HP_SMALL_TIMING_AVAIL):
	Likewise.
	* sysdeps/powerpc/powerpc32/power4/hp-timing.h (HP_TIMING_AVAIL,
	HP_SMALL_TIMING_AVAIL): Likewise.
	* sysdeps/powerpc/powerpc64/hp-timing.h (HP_TIMING_AVAIL,
	HP_SMALL_TIMING_AVAIL): Likewise.
	* sysdeps/sparc/sparc32/sparcv9/hp-timing.h (HP_TIMING_AVAIL,
	HP_SMALL_TIMING_AVAIL): Likewise.
	* sysdeps/sparc/sparc64/hp-timing.h (HP_TIMING_AVAIL,
	HP_SMALL_TIMING_AVAIL): Likewise.
	* sysdeps/x86/hp-timing.h (HP_TIMING_AVAIL, HP_SMALL_TIMING_AVAIL):
	Likewise.
	* sysdeps/generic/hp-timing-common.h: Update comment with
	HP_TIMING_AVAIL removal.