IA64: Increase maximum physmem size to cover 8 petabyte

We currently can support these large configurations only with Discontigmem.

Increase sparsemems max physmem bits to also be able to handle 8 petabyte.

Discontigmem supports up to 16 petabyte but I will need to use bit 53 to flag
vmemmap addresses for the TLB handler. It seems that the currently used bit 60
is not supported by a certain virtualization technique.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.22-rc2/include/asm-ia64/sparsemem.h
===================================================================
--- linux-2.6.22-rc2.orig/include/asm-ia64/sparsemem.h	2007-05-22 17:28:04.000000000 -0700
+++ linux-2.6.22-rc2/include/asm-ia64/sparsemem.h	2007-05-22 17:28:37.000000000 -0700
@@ -8,7 +8,7 @@
  */
 
 #define SECTION_SIZE_BITS	(30)
-#define MAX_PHYSMEM_BITS	(50)
+#define MAX_PHYSMEM_BITS	(53)
 #ifdef CONFIG_FORCE_MAX_ZONEORDER
 #if ((CONFIG_FORCE_MAX_ZONEORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS)
 #undef SECTION_SIZE_BITS