Current pci_get_interrupt_pin() seems to have an assumption that
pci_bus->self is NULL on the root pci bus. But it might not be true on
some platforms. Because of this wrong assumption, current
pci_get_interrupt_pin() might cause endless loop. We must check
pci_bus->parent instead.
Signed-off-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>