powerpc/PCI: convert devtree bus addresses to resource

Normal PCI enumeration via PCI config space uses __pci_read_base(), where
the PCI core applies any bus-to-resource offset.  But powerpc doesn't use
that path when enumerating via the device tree.

In 6c5705fe, I converted powerpc to use the PCI core bus-to-resource
conversion, but I missed these powerpc-specific paths.  Some powerpc
platforms fail to boot ("Cannot allocate resource region," "device not
available," etc.) between that commit and this one.

This adds the corresponding bus-to-resource conversion in the paths that
read BAR values from the OF device tree.

CC: Anton Blanchard <anton@samba.org>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>