pio_addr_t is almost unused, because these days I/O ports are simply
accessed through the address space. cpu_{in,out}[bwl] themselves are
almost unused; monitor.c and xen-hvm.c could use address_space_read/write
directly, since they have an integer size at hand. This leaves qtest as
the only user of those functions.
On the other hand even portio_* functions use this type; the only
interesting use of pio_addr_t thus is include/hw/sysbus.h. I guess I
could move it there, but I don't see much benefit in that either. Using
uint32_t is enough and avoids the need to include ioport.h everywhere.
Backports commit 89a80e7400f7225d9401b35ef32454b4ab29dc67 from qemu
