powerpc: ceil/ceilf refactor

This patches consolidates all the powerpc ceil{f} implementations on
the generic sysdeps/powerpc/fpu/s_ceil{f}.  The generic implementation
uses either the compiler builts for ISA 2.03+ (which generates the frip
instruction) or a generic implementation which uses FP only operations.

It adds a generic implementation (round_to_integer.h) which is shared
with other rounding to integer routines.  The resulting code should be
similar in term os performance to previous assembly one.

The IFUNC organization for powerpc64 is also change to be enabled only
for powerpc64 and not for powerpc64le (since minium ISA of 2.08 does not
require the fallback generic implementation).

Checked on powerpc-linux-gnu (built without --with-cpu, with
--with-cpu=power4 and with --with-cpu=power5+ and --disable-multi-arch),
powerpc64-linux-gnu (built without --with-cp and with --with-cpu=power5+
and --disable-multi-arch).

	* sysdeps/powerpc/fpu/fenv_libc.h (__fesetround_inline_nocheck): New
	function.
	* sysdeps/powerpc/fpu/round_to_integer.h: New file.
	* sysdeps/powerpc/fpu/s_ceil.c: Likewise.
	* sysdeps/powerpc/fpu/s_ceilf.c: Likewise.
	* sysdeps/powerpc/powerpc32/fpu/s_ceil.S: Remove file.
	* sysdeps/powerpc/powerpc32/fpu/s_ceilf.S: Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/Makefile
	(CFLAGS-s_ceil-power5+.c, CFLAGS-s_ceilf-power5+.c): New rule.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_ceil-power5+.S:
	Remove file.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_ceil-ppc32.S:
	Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_ceilf-power5+.S:
	Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_ceilf-ppc32.S:
	Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_ceil-power5+.c:
	New file.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_ceil-ppc32.c:
	Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_ceilf-power5+.c:
	Likewise.
	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_ceilf-ppc32.c:
	Likewise.
	* sysdeps/powerpc/powerpc32/power5+/fpu/s_ceil.S: Remove file.
	* sysdeps/powerpc/powerpc32/power5+/fpu/s_ceilf.S: Likewise.
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/Makefile: New file.
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_ceil-power5+.c:
	Likewise.
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_ceil-ppc64.c:
	Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_ceil.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_ceil.c: ... here.
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_ceilf-power5+.c: New
	file.
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_ceilf-ppc64.c:
	Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_ceilf.c: Move to ...
	* sysdeps/powerpc/powerpc64/be/fpu/multiarch/s_ceilf.c: ...
	* here.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
	(libm-sysdep_routines): Remove s_ceil-power5+, s_ceil-ppc64,
	s_ceilf-power5+, and s_ceilf-ppc64.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_ceil-power5+.S: Remove
	file.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_ceil-ppc64.S: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_ceilf-power5+.S: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_ceilf-ppc64.S: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/s_ceil.S: Likewise.
	* sysdeps/powerpc/powerpc64/fpu/s_ceilf.S: Likewise.
	* sysdeps/powerpc/powerpc64/power5+/fpu/s_ceil.S: Likewise.
	* sysdeps/powerpc/powerpc64/power5+/fpu/s_ceilf.S: Likewise.

Reviewed-by: Gabriel F. T. Gomes <gabriel@inconstante.eti.br>