x86-irq-2020-10-12

devices which require non-PCI based MSI handling.

  - Cleanup historical leftovers all over the place

  - Rework the code to utilize more core functionality

  - Wrap XEN PCI/MSI interrupts into an irqdomain to make irqdomain
    assignment to PCI devices possible.

  - Assign irqdomains to PCI devices at initialization time which allows
    to utilize the full functionality of hierarchical irqdomains.

  - Remove arch_.*_msi_irq() functions from X86 and utilize the irqdomain
    which is assigned to the device for interrupt management.

  - Make the arch_.*_msi_irq() support conditional on a config switch and
    let the last few users select it.