[IA64] Cleanup use of various #defines related to nodes

Some of the SN code & #defines related to compact nodes & IO discovery
have gotten stale over the years. This patch attempts to clean them up.
Some of the various SN MAX_xxx #defines were also unclear & misused.

The primary changes are:

	- use MAX_NUMNODES. This is the generic linux #define for the number
	  of nodes that are known to the generic kernel. Arrays & loops
	  for constructs that are 1:1 with linux-defined nodes should
	  use the linux #define - not an SN equivalent.

	- use MAX_COMPACT_NODES for MAX_NUMNODES + NUM_TIOS. This is the
	  number of nodes in the SSI system. Compact nodes are a hack to
	  get around the IA64 architectural limit of 256 nodes. Large SGI
	  systems have more than 256 nodes. When we upgrade to ACPI3.0,
	  I _hope_ that all nodes will be real nodes that are known to
	  the generic kernel. That will allow us to delete the notion
	  of "compact nodes".

	- add MAX_NUMALINK_NODES for the total number of nodes that
	  are in the numalink domain - all partitions.

	- simplified (understandable) scan_for_ionodes()

	- small amount of cleanup related to cnodes

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/include/asm-ia64/sn/xp.h b/include/asm-ia64/sn/xp.h
index 1df1c9f..75a2f39 100644
--- a/include/asm-ia64/sn/xp.h
+++ b/include/asm-ia64/sn/xp.h
@@ -49,7 +49,7 @@
  * C-brick nasids, thus the need for bitmaps which don't account for
  * odd-numbered (non C-brick) nasids.
  */
-#define XP_MAX_PHYSNODE_ID	(MAX_PHYSNODE_ID / 2)
+#define XP_MAX_PHYSNODE_ID	(MAX_NUMALINK_NODES / 2)
 #define XP_NASID_MASK_BYTES	((XP_MAX_PHYSNODE_ID + 7) / 8)
 #define XP_NASID_MASK_WORDS	((XP_MAX_PHYSNODE_ID + 63) / 64)