copper: Fix SCRATCH_ADDR base and size.

Change-Id: I8569f16bb84300a4fc90e285b9a4add3b75555f5
diff --git a/target/copper/meminfo.c b/target/copper/meminfo.c
index 2f2fdcc..c8460bb 100644
--- a/target/copper/meminfo.c
+++ b/target/copper/meminfo.c
@@ -118,5 +118,9 @@
 	return ((void *)SCRATCH_ADDR);
 }
 
+unsigned target_get_max_flash_size(void)
+{
+	return (512 * 1024 * 1024);
+}
 #endif /* DEVICE_TREE */