Pin and MSI interrupt handling arm64

In arm hw_pci->map_irq is used to map irq number, and struct msi_chip containing details of setup_irq and teardown_irq is assigned to msi_chip in struct pci_bus in using hw_pci->add_bus.

How PIN and MSI interrupt details are being handled/assigned by pci subsystem in arm64, since struct hw_pci is absent in arm64.

Regards
Bharat