[POWERPC] Add 64-bit resources support to pci_iomap

The patch adds support for the 64-bit resources to the PCI
iomap code.

Signed-off-by: Valentine Barshak <vbarshak@ru.mvista.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>