[S390] Add support for memory hot-add.

Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/include/asm-s390/sparsemem.h b/include/asm-s390/sparsemem.h
index 06dfdab..545d219 100644
--- a/include/asm-s390/sparsemem.h
+++ b/include/asm-s390/sparsemem.h
@@ -1,15 +1,15 @@
 #ifndef _ASM_S390_SPARSEMEM_H
 #define _ASM_S390_SPARSEMEM_H
 
-#define SECTION_SIZE_BITS	25
-
 #ifdef CONFIG_64BIT
 
+#define SECTION_SIZE_BITS	28
 #define MAX_PHYSADDR_BITS	42
 #define MAX_PHYSMEM_BITS	42
 
 #else
 
+#define SECTION_SIZE_BITS	25
 #define MAX_PHYSADDR_BITS	31
 #define MAX_PHYSMEM_BITS	31