powerpc/powernv: Don't use pe->pbus to get the domain number

If the PE contains single PCI function, "pe->pbus" would be NULL.
It's not reliable to be used by pci_domain_nr(). We just grab the
PCI domain number from the PCI host controller (struct pci_controller)
instance.

Signed-off-by: Gavin Shan <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

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

···
 				 TCE_PCI_SWINV_PAIR);
 	}
 	iommu_init_table(tbl, phb->hose->node);
-	iommu_register_group(tbl, pci_domain_nr(pe->pbus), pe->pe_number);
+	iommu_register_group(tbl, phb->hose->global_number, pe->pe_number);
 
 	if (pe->pdev)
 		set_iommu_table_base_and_group(&pe->pdev->dev, tbl);
···
 		tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE);
 	}
 	iommu_init_table(tbl, phb->hose->node);
-	iommu_register_group(tbl, pci_domain_nr(pe->pbus), pe->pe_number);
+	iommu_register_group(tbl, phb->hose->global_number, pe->pe_number);
 
 	if (pe->pdev)
 		set_iommu_table_base_and_group(&pe->pdev->dev, tbl);