memblock: Export MEMBLOCK_ERROR

will used by x86 memblock_x86_find_in_range_node and nobootmem replacement

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index eed0f9b..1a9c29c 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -18,7 +18,8 @@
 
 #include <asm/memblock.h>
 
-#define INIT_MEMBLOCK_REGIONS 128
+#define INIT_MEMBLOCK_REGIONS	128
+#define MEMBLOCK_ERROR		(~(phys_addr_t)0)
 
 struct memblock_region {
 	phys_addr_t base;