PCI: Make pci_setup_bridge() non-static for use by arch code

The "powernv" platform of the powerpc architecture needs to assign PCI
resources using a specific algorithm to fit some HW constraints of
the IBM "IODA" architecture (related to the ability to create error
handling domains that encompass specific segments of MMIO space).

For doing so, it wants to call pci_setup_bridge() from architecture
specific resource management in order to configure bridges after all
resources have been assigned. So make it non-static.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>