This patch changes the SN macros for calulating the addresses
of shub MMRs. Functionally, shub1 (current chipset) and shub2
are very similar. The primary differences are in the addresses
of MMRs and in the location of the NASID (node number) in
a physical address. This patch adds the basic infrastructure
for running a single binary kernel image on either shub1 or shub2.
Signed-off-by: Jack Steiner <steiner@sgi.com>