MIPS: cavium-octeon: fix I/O space setup on non-PCI systems

Fix I/O space setup, so that on non-PCI systems using inb()/outb()
won't crash the system. Some drivers may try to probe I/O space and for
that purpose we can just allocate some normal memory initially. Drivers
trying to reserve a region will fail early as we set the size to 0. If
a real I/O space is present, the PCI/PCIe support code will re-adjust
the values accordingly.

Tested with EdgeRouter Lite by enabling CONFIG_SERIO_I8042 that caused
the originally reported crash.

Reported-by: Faidon Liambotis <paravoid@debian.org>
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5626/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>