linux-user: add hppa magic numbers in qemu-binfmt-conf.sh

As we have now a linux-user HPPA target, we can add it to the list of
supported targets in qemu-binfmt-conf.sh

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-Id: <20170126080449.28255-2-laurent@vivier.eu>
Signed-off-by: Richard Henderson <rth@twiddle.net>