MIPS: pci-legacy: Override pci_address_to_pio

pci-legacy systems are not using logic_pio to managed PIO
allocations, thus the generic pci_address_to_pio won't work
when PCI_IOBASE is defined.

Override the function to use architecture implementation to
fix the problem.

Cc: stable@vger.kernel.org
Fixes: 4bfb53e7 ("mips: add <asm-generic/io.h> including")
Reported-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Closes: https://lore.kernel.org/r/99f75c66-4c2d-45dc-a808-b5ba440c7551@app.fastmail.com/


Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>