lib: add NO_GENERIC_PCI_IOPORT_MAP

Some architectures need to override the way
IO port mapping is done on PCI devices.
Supply a generic macro that calls
ioport_map, and make it possible for architectures
to override.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>