hppa: set __IPC_64 as zero for SysV IPC calls

    In 1e5834c3 ("Refactor Linux ipc_priv header") a different
    approach to passing __IPC_64 as zero was created.  Hppa kernel ABI
    requires to oass __IPC_64 as zero since it does not set
    CONFIG_ARCH_WANT_IPC_PARSE_VERSION in the kernel.

    Checked on hppa-linux-gnu with some adjustments to avoid BZ#21016
    (basically by removing hppa compat implementations and adjusting
    required headers).

            * sysdeps/unix/sysv/linux/hppa/ipc_priv.h: New file.