of/pci: Fix the conversion of IO ranges into IO resources
The ranges property for a host bridge controller in DT describes the
mapping between the PCI bus address and the CPU physical address. The
resources framework however expects that the IO resources start at a pseudo
"port" address 0 (zero) and have a maximum size of IO_SPACE_LIMIT. The
conversion from PCI ranges to resources failed to take that into account,
returning a CPU physical address instead of a port number.
Also fix all the drivers that depend on the old behaviour by fetching the
CPU physical address based on the port number where it is being needed.