PCI: Add bridge DMA alias quirk for ITE bridge

The ITE 8892 is a PCIe-to-PCI bridge but doesn't have a PCIe capability.
Quirk it so we can figure out the DMA alias for devices below the bridge,
so they work correctly with an IOMMU.

[bhelgaas: add changelog]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=73551


Reported-by: Ronald <rwarsow@gmx.de>
Tested-by: Ronald <rwarsow@gmx.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>