Merge branch 'pci/controller/loongson'

- Ignore downstream devices only on internal bridges to avoid Loongson
  hardware issue (Rong Zhang)

- Quirk old Loongson-3C6000 bridges that advertise incorrect supported link
  speeds (Ziyao Li)

* pci/controller/loongson:
  PCI: loongson: Override PCIe bridge supported speeds for Loongson-3C6000 series
  PCI: loongson: Do not ignore downstream devices on external bridges