MFC r304459,r305527:

MFC r304459,r305527:

  r304459:
    INTRNG: Rework handling with resources. Partially revert r301453.
     - Read interrupt properties at bus enumeration time and store
       it into global mapping table.
     - At bus_activate_resource() time, given mapping entry is resolved and
       connected to real interrupt source. A copy of mapping entry is attached
       to given resource.
     - At bus_setup_intr() time, mapping entry stored in resource is used
       for delivery of requested interrupt configuration.
     - For MSI/MSIX interrupts, mapping entry is created within
       pci_alloc_msi()/pci_alloc_msix() call.
     - For legacy PCI interrupts, mapping entry must be created within
       pcib_route_interrupt() by pcib driver itself.
  r305527:
    Fix MIPS INTRNG (both FDT and non-FDT) behaviour broken by r304459