"Rework enabling/disabling of ATS for PCI masters" failed to compile on arm64

[Qian Cai]

The linux-next commit âiommu/arm-smmu-v3: Rework enabling/disabling of ATS for PCI mastersâ [1] causes a compilation error when PCI_ATS=n on arm64.

[1] https://lore.kernel.org/linux-iommu/20190820154549.17018-3-will@xxxxxxxxxx/

drivers/iommu/arm-smmu-v3.c:2325:35: error: no member named 'ats_cap' in 'struct pci_dev'
        return !pdev->untrusted && pdev->ats_cap;
                                   ~~~~  ^

For example,

Symbol: PCI_ATS [=n]
  â Type  : bool
  â   Defined at drivers/pci/Kconfig:118
  â   Depends on: PCI [=y] 
  â   Selected by [n]: 
  â   - PCI_IOV [=n] && PCI [=y] 
  â   - PCI_PRI [=n] && PCI [=y]â  
  â   - PCI_PASID [=n] && PCI [=y] â  
  â   - AMD_IOMMU [=n] && IOMMU_SUPPORT [=y] && X86_64 && PCI [=y] && ACPI [=y]