powerpc/powernv: Move pnv_ioda_setup_bus_dma under CONFIG_IOMMU_API

pnv_ioda_setup_bus_dma() is only used when a passed through PE is
returned to the host. If the kernel is built without IOMMU support
this is dead code. Move it under the #ifdef with the rest of the
IOMMU API support.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200705133557.443607-2-oohall@gmail.com

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -1885,19 +1885,6 @@ static bool pnv_pci_ioda_iommu_bypass_supported(struct pci_dev *pdev,
 	return false;
 }
 
-static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe, struct pci_bus *bus)
-{
-	struct pci_dev *dev;
-
-	list_for_each_entry(dev, &bus->devices, bus_list) {
-		set_iommu_table_base(&dev->dev, pe->table_group.tables[0]);
-		dev->dev.archdata.dma_offset = pe->tce_bypass_base;
-
-		if ((pe->flags & PNV_IODA_PE_BUS_ALL) && dev->subordinate)
-			pnv_ioda_setup_bus_dma(pe, dev->subordinate);
-	}
-}
-
 static inline __be64 __iomem *pnv_ioda_get_inval_reg(struct pnv_phb *phb,
 						     bool real_mode)
 {
@@ -2547,6 +2534,19 @@ static long pnv_pci_ioda2_create_table_userspace(
 	return ret;
 }
 
+static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe, struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		set_iommu_table_base(&dev->dev, pe->table_group.tables[0]);
+		dev->dev.archdata.dma_offset = pe->tce_bypass_base;
+
+		if ((pe->flags & PNV_IODA_PE_BUS_ALL) && dev->subordinate)
+			pnv_ioda_setup_bus_dma(pe, dev->subordinate);
+	}
+}
+
 static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group)
 {
 	struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe,