To properly fix PCI hotplug, it's useful to be able to make the fixup
passes on all devices whether they were just hot plugged or already
there.

However, pcibios_allocate_bus_resources() wouldn't cope well with
being called twice for a given bus.  This makes it ignore resources
that have already been allocated, along with adding a bit of debug
output.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>