powerpc: Drop archdata numa_node

Use the struct device's numa_node instead; use accessor functions
to get/set numa_node.

Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index 44e3486..124f867 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -29,7 +29,7 @@
 {
 	struct page *page;
 	void *ret;
-	int node = dev->archdata.numa_node;
+	int node = dev_to_node(dev);
 
 	page = alloc_pages_node(node, flag, get_order(size));
 	if (page == NULL)