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 -durN gcc-3.4.6.orig/gcc/config/sh/sh.h gcc-3.4.6/gcc/config/sh/sh.h

--- gcc-3.4.6.orig/gcc/config/sh/sh.h	2006-01-12 02:20:32.000000000 +0100

+++ gcc-3.4.6/gcc/config/sh/sh.h	2007-08-15 23:03:09.000000000 +0200

@@ -422,6 +422,10 @@

 do {									\

   if (LEVEL)								\

     flag_omit_frame_pointer = -1;					\

+  if (LEVEL <= 2)							\

+    {									\

+      flag_reorder_blocks = 0;						\

+    }									\

   if (SIZE)								\

     target_flags |= SPACE_BIT;						\

   if (TARGET_SHMEDIA && LEVEL > 1)					\