asm-generic: fix inX/outX functions for architectures that have PCI

The definitions for the PC-style PIO functions in asm-generic/io.h were
meant as dummies so you could compile code on architectures without
ISA and PCI buses. However, unicore32 actually wants to use them
with a real PCI bus, so they need to be defined to actually address
the register window holding the I/O ports.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>