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-4.3.2.orig/libgcc/config/sh/t-linux gcc-4.3.2/libgcc/config/sh/t-linux

--- gcc-4.3.2.orig/libgcc/config/sh/t-linux	2009-03-07 11:42:38.000000000 +0100

+++ gcc-4.3.2/libgcc/config/sh/t-linux	2009-03-07 11:03:39.000000000 +0100

@@ -15,7 +15,7 @@

 	-Wl,--soname=@shlib_base_name@.so.1 \

 	-Wl,--version-script=@shlib_map_file@ \

 	-o @multilib_dir@/@shlib_base_name@.so.1.tmp @multilib_flags@ \

-	@shlib_objs@ -lc && \

+	@shlib_objs@ && \

 	rm -f @multilib_dir@/@shlib_base_name@.so && \

 	if [ -f @multilib_dir@/@shlib_base_name@.so.1 ]; then \

 	  mv -f @multilib_dir@/@shlib_base_name@.so.1 \