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 -urN uClibc-dist/libc/sysdeps/linux/common/bits/uClibc_touplow.h uClibc/libc/sysdeps/linux/common/bits/uClibc_touplow.h

--- uClibc-dist/libc/sysdeps/linux/common/bits/uClibc_touplow.h   Fri Jun  3 13:30:25 2005

+++ uClibc/libc/sysdeps/linux/common/bits/uClibc_touplow.h   Fri Jun  3 13:30:39 2005

@@ -34,11 +34,11 @@

 /* glibc uses the equivalent of - typedef __int32_t __ctype_touplow_t; */

-typedef __uint16_t __ctype_mask_t;

+typedef __uint32_t __ctype_mask_t;

 #ifdef __UCLIBC_HAS_CTYPE_SIGNED__

-typedef __int16_t __ctype_touplow_t;

+typedef __int32_t __ctype_touplow_t;

 #define __UCLIBC_CTYPE_B_TBL_OFFSET       128

 #define __UCLIBC_CTYPE_TO_TBL_OFFSET      128