powerpc/PCI: split PHB part out of pcibios_map_io_space()

No functional change.  This is so we can use pcibios_phb_map_io_space()
before we have a struct pci_bus.

v2: fix map io phb typo

CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
1 file changed