linux-user: Separate binfmt arm CPU families

linux-user: Separate binfmt arm CPU families

Give big-endian arm and aarch64 CPUs their own family in
qemu-binfmt-conf.sh to make sure we register qemu-user for binaries of
the opposite endianness on arm and aarch64. Apart from the family
assignments of the magic values, qemu_get_family() needs to be able to
distinguish the two and recognise aarch64{,_be} as well.

Signed-off-by: Michael Weiser <michael.weiser@gmx.de>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-id: 20171220212308.12614-7-michael.weiser@gmx.de
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>