[IA64-SGI] - New SN hardware support - boot_init_shub2

Update the addresses of the pio_write_status_addr so that
they are correct for newer processors. Shub2 did not number
the threads in the order that I had expected.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>