powerpc/mm: Add 64TB support

Increase max addressable range to 64TB. This is not tested on
real hardware yet.

Reviewed-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/pgtable-ppc64-4k.h b/arch/powerpc/include/asm/pgtable-ppc64-4k.h
index d6489a2..12798c9 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64-4k.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64-4k.h
@@ -7,7 +7,7 @@
  */
 #define PTE_INDEX_SIZE  9
 #define PMD_INDEX_SIZE  7
-#define PUD_INDEX_SIZE  7
+#define PUD_INDEX_SIZE  9
 #define PGD_INDEX_SIZE  9
 
 #ifndef __ASSEMBLY__