arch/powerpc: add powerpc64le support

Technically, I don't forbid powerpcle support either, but I'm not sure that
there is any library/compiler support for that at the moment (though the hw
technically makes it possible).

powerpc64le needs glibc 2.19 and gcc 4.9. I haven't looked into the support
tools, but at least gdb 7.5 is too old (7.7.1 definitely has support).

Also make powerpc64 non-experimental. It's practically old at this point.

Signed-off-by: Cody P Schafer <dev@codyps.com>
[yann.morin.1998@free.fr: use ${target_endian_le} and ${target_bits_64}]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <64bfbbced9dd8f62e0d6.1399801945@gun>
Patchwork-Id: 347775

diff -urN glibc-2.10.1-orig/manual/Makefile glibc-2.10.1/manual/Makefile

--- glibc-2.10.1-orig/manual/Makefile 2006-01-07 22:43:47.000000000 -0800

+++ glibc-2.10.1/manual/Makefile 2014-01-15 11:49:08.256982014 -0800

@@ -232,7 +232,11 @@

 .PHONY: stubs

 stubs: $(objpfx)stubs

 endif

-$(objpfx)stubs ../po/manual.pot $(objpfx)stamp%:

+$(objpfx)stamp%:

+	$(make-target-directory)

+	touch $@

+

+$(objpfx)stubs ../po/manual.pot:

 	$(make-target-directory)

 	touch $@