On the PCI plugging event, PCI slot's subordinate devices are
scanned and their (IO and MMIO) resources are assigned. Platform
dependent resources (PE#, IO/MMIO/DMA windows) are allocated or
created on updating windows of the slot's upstream bridge.
This updates the windows of the hot plugged slot's upstream bridge
in pcibios_finish_adding_to_bus() so that the platform resources
(PE#, IO/MMIO/DMA segments) are allocated or created accordingly.