Fix the compile error below (CONFIG_PCI_ATS not set):
drivers/iommu/intel/dmar.c: In function ‘vf_inherit_msi_domain’:
drivers/iommu/intel/dmar.c:338:59: error: ‘struct pci_dev’ has no member named ‘physfn’; did you mean ‘is_physfn’?
338 | dev_set_msi_domain(&pdev->dev, dev_get_msi_domain(&pdev->physfn->dev));
| ^~~~~~
| is_physfn