sched: Allow SD_NODES_PER_DOMAIN to be overridden

We want to override the default value of SD_NODES_PER_DOMAIN on ppc64,
so move it into linux/topology.h.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/include/linux/topology.h b/include/linux/topology.h
index fc839bf..e26db03 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -201,6 +201,10 @@
 	.balance_interval	= 64,					\
 }
 
+#ifndef SD_NODES_PER_DOMAIN
+#define SD_NODES_PER_DOMAIN 16
+#endif
+
 #ifdef CONFIG_SCHED_BOOK
 #ifndef SD_BOOK_INIT
 #error Please define an appropriate SD_BOOK_INIT in include/asm/topology.h!!!