powerpc/pseries: Do not need to check for dma_window == NULL

The block in pci_dma_dev_setup_pSeriesLP for dma_window == NULL can be
removed because we will only teminate the loop if we had already allocated
a iommu table for that node or we found a window.  While there may be
no window for the device, the intresting part is if we are reusing a
table or creating it for the first device under it.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/pseries/iommu.c

@@ -530,12 +530,6 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
 	}
 	pr_debug("  parent is %s\n", pdn->full_name);
 
-	if (dma_window == NULL) {
-		pr_debug("  no dma window for device, linking to parent\n");
-		set_iommu_table_base(&dev->dev, PCI_DN(pdn)->iommu_table);
-		return;
-	}
-
 	pci = PCI_DN(pdn);
 	if (!pci->iommu_table) {
 		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,