powerpc: Change archdata dma_data to a union

Sometimes this is used to hold a simple offset, and sometimes
it is used to hold a pointer.  This patch changes it to a union containing
void * and dma_addr_t.  get/set accessors are also provided, because it was
getting a bit ugly to get to the actual data.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 661c8e0..1a0000a 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -482,7 +482,7 @@
 				   phb->node);
 		iommu_table_setparms(phb, dn, tbl);
 		PCI_DN(dn)->iommu_table = iommu_init_table(tbl, phb->node);
-		dev->dev.archdata.dma_data = PCI_DN(dn)->iommu_table;
+		set_iommu_table_base(&dev->dev, PCI_DN(dn)->iommu_table);
 		return;
 	}
 
@@ -494,7 +494,7 @@
 		dn = dn->parent;
 
 	if (dn && PCI_DN(dn))
-		dev->dev.archdata.dma_data = PCI_DN(dn)->iommu_table;
+		set_iommu_table_base(&dev->dev, PCI_DN(dn)->iommu_table);
 	else
 		printk(KERN_WARNING "iommu: Device %s has no iommu table\n",
 		       pci_name(dev));
@@ -538,7 +538,7 @@
 	 */
 	if (dma_window == NULL || pdn->parent == NULL) {
 		pr_debug("  no dma window for device, linking to parent\n");
-		dev->dev.archdata.dma_data = PCI_DN(pdn)->iommu_table;
+		set_iommu_table_base(&dev->dev, PCI_DN(pdn)->iommu_table);
 		return;
 	}
 
@@ -554,7 +554,7 @@
 		pr_debug("  found DMA window, table: %p\n", pci->iommu_table);
 	}
 
-	dev->dev.archdata.dma_data = pci->iommu_table;
+	set_iommu_table_base(&dev->dev, pci->iommu_table);
 }
 #else  /* CONFIG_PCI */
 #define pci_dma_bus_setup_pSeries	NULL