ARM: iop13xx: use fixed PCI i/o mapping

Move iop13xx PCI to fixed i/o mapping and remove io.h.

This changes the PCIe bus address to start at 0x10000. Let's hope this
works. If it does not, the alternative would be to revert the value we
write into OIOTVR to zero and set sys->io_offset to 64K.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>