With some newer UEFI firmware, not all pci bars get
programmed and we have to assign them ourselfs.
This was already done for memory bars. This change
adds the same for i/o port space, by providing a
ioreservewin() function which can be used to allocate
port space within the parent pci-pci bridge window.
Also, the pci code now allocates the pci config
space i/o ports 0xCF8/0xCFC so userspace needs to
use devpnp to access pci config space now. (see
latest realemu change).
Also, this moves the ioalloc()/iofree() code out
of devarch into port/iomap.c as it can be shared
with the ppc mtx kernel.
0ba91ae22a