arch/powerpc: Move dma_mask from of_device into pdev_archdata

By moving dma_mask into pdev_archdata, and adding archdata to
struct of_device, it makes it possible to substitute of_device
with struct platform_device, which is a stepping stone to
removing the of_platform bus entirely.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/powerpc/kernel/of_device.c b/arch/powerpc/kernel/of_device.c
index 20b3474..df78e02 100644
--- a/arch/powerpc/kernel/of_device.c
+++ b/arch/powerpc/kernel/of_device.c
@@ -70,7 +70,7 @@
 		return NULL;
 
 	dev->dev.of_node = of_node_get(np);
-	dev->dev.dma_mask = &dev->dma_mask;
+	dev->dev.dma_mask = &dev->archdata.dma_mask;
 	dev->dev.parent = parent;
 	dev->dev.release = of_release_dev;
 
diff --git a/arch/powerpc/kernel/of_platform.c b/arch/powerpc/kernel/of_platform.c
index 1c747c4..2188534 100644
--- a/arch/powerpc/kernel/of_platform.c
+++ b/arch/powerpc/kernel/of_platform.c
@@ -74,7 +74,7 @@
 	if (!dev)
 		return NULL;
 
-	dev->dma_mask = 0xffffffffUL;
+	dev->archdata.dma_mask = 0xffffffffUL;
 	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 
 	dev->dev.bus = &of_platform_bus_type;