parisc/PCI: register busn_res for root buses

parisc/PCI: register busn_res for root buses

Add the host bridge bus number aperture to the resource list.
Like the MMIO and I/O port apertures, this is used when assigning
resources to hot-added devices or in the case of conflicts.

[bhelgaas: changelog, set flags directly, at LBA bus_num init]
CC: Kyle McMartin <[email protected]>
CC: Helge Deller <[email protected]>
CC: [email protected]
Signed-off-by: Yinghai Lu <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>