powerpc/powernv/npu: Remove dead iommu code

PNV_IODA_PE_DEV is only used for NPU devices (emulated PCI bridges
representing NVLink). These are added to IOMMU groups with corresponding
NVIDIA devices after all non-NPU PEs are setup; a special helper -
pnv_pci_ioda_setup_iommu_api() - handles this in pnv_pci_ioda_fixup().

The pnv_pci_ioda2_setup_dma_pe() helper sets up DMA for a PE. It is called
for VFs (so it does not handle NPU case) and PCI bridges but only
IODA1 and IODA2 types. An NPU bridge has its own type id (PNV_PHB_NPU)
so pnv_pci_ioda2_setup_dma_pe() cannot be called on NPU and therefore
(pe->flags & PNV_IODA_PE_DEV) is always "false".

This removes not used iommu_add_device(). This should not cause any
behavioral change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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

@@ -2735,9 +2735,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	if (rc)
 		return;
 
-	if (pe->flags & PNV_IODA_PE_DEV)
-		iommu_add_device(&pe->pdev->dev);
-	else if (pe->flags & (PNV_IODA_PE_BUS | PNV_IODA_PE_BUS_ALL))
+	if (pe->flags & (PNV_IODA_PE_BUS | PNV_IODA_PE_BUS_ALL))
 		pnv_ioda_setup_bus_dma(pe, pe->pbus, true);
 }