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

# Compute MIPS-specific values

CT_DoArchTupleValues() {

    local _64

    # The architecture part of the tuple

    if [ "${CT_ARCH_64}" = "y" ]; then

        _64="64"

    fi

    CT_TARGET_ARCH="${CT_ARCH}${_64}${CT_ARCH_SUFFIX:-${target_endian_el}}"

    # Override CFLAGS for endianness:

    case "${CT_ARCH_ENDIAN}" in

        big)    CT_ARCH_ENDIAN_CFLAG="-EB";;

        little) CT_ARCH_ENDIAN_CFLAG="-EL";;

    esac

    # Override ABI flags

    CT_ARCH_ABI_CFLAG="-mabi=${CT_ARCH_mips_ABI}"

    CT_ARCH_WITH_ABI="--with-abi=${CT_ARCH_mips_ABI}"

}