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 -dur strace-4.5.16.orig/syscall.c strace-4.5.16/syscall.c

 --- strace-4.5.16.orig/syscall.c	2007-07-14 19:21:44.000000000 +0200

 +++ strace-4.5.16/syscall.c	2007-07-14 19:22:49.000000000 +0200

 @@ -125,6 +125,18 @@

  #define TP TRACE_PROCESS

  #define TS TRACE_SIGNAL

 +#ifndef HAVE_STATFS64

 +/*

 + * Ugly hacks for systems that do not have LFS

 + */

 +

 +#define sys_truncate64  sys_truncate

 +#define sys_ftruncate64 sys_ftruncate

 +#define sys_getdents64  sys_getdents

 +#define sys_statfs64    sys_statfs

 +#define sys_fstatfs64   sys_fstatfs

 +#endif

 +

  static const struct sysent sysent0[] = {

  #include "syscallent.h"

  };