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

Original patch from gentoo: ../../dev/crosstool-NG/ct-ng.trunk/patches/strace/4.5.17/150-undef-CTL_PROC.patch

-= BEGIN original header =-

diff -dur strace-4.5.16.orig/system.c strace-4.5.16/system.c

-= END original header =-

diff -durN strace-4.5.17.orig/system.c strace-4.5.17/system.c

--- strace-4.5.17.orig/system.c	2007-01-17 00:22:36.000000000 +0100

+++ strace-4.5.17/system.c	2008-10-24 21:30:13.000000000 +0200

@@ -1612,7 +1612,9 @@

 	{ CTL_KERN, "CTL_KERN" },

 	{ CTL_VM, "CTL_VM" },

 	{ CTL_NET, "CTL_NET" },

+#ifdef CTL_PROC

 	{ CTL_PROC, "CTL_PROC" },

+#endif

 	{ CTL_FS, "CTL_FS" },

 	{ CTL_DEBUG, "CTL_DEBUG" },

 	{ CTL_DEV, "CTL_DEV" },