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

timezone data has been split into the package sys-libs/timezone-data

diff -durN glibc-2.12.1.orig/Makeconfig glibc-2.12.1/Makeconfig

--- glibc-2.12.1.orig/Makeconfig	2009-11-13 00:50:13.000000000 +0100

+++ glibc-2.12.1/Makeconfig	2009-11-13 00:50:41.000000000 +0100

@@ -944,7 +944,7 @@

 	      stdlib stdio-common libio malloc string wcsmbs time dirent    \

 	      grp pwd posix io termios resource misc socket sysvipc gmon    \

 	      gnulib iconv iconvdata wctype manual shadow gshadow po argp   \

-	      crypt nss localedata timezone rt conform debug		    \

+	      crypt nss localedata rt conform debug		    \

 	      $(add-on-subdirs) $(dlfcn) $(binfmt-subdir)

 ifndef avoid-generated