d it by attempting to reserve legacy regions
before we try to assign addresses.

NOTE: This may have nasty side effects in cases I haven't tested
yet:

 - We try to use FW mappings (ie. powermac) and the FW has allocated
a conflicting address over those legacy regions. This will typically
happen. I would expect the new code to just fail with an informative
message without harm but I haven't had a chance to test that scenario
yet.

 - A device with fixed BARs overlapping those legacy addresses such
as an IDE controller in legacy mode is in the system. I don't know
for sure yet what will happen there, I have to test :-)

Ideally, we should change PCIBIOS_MIN_IO/MIN_MEM accross the board
to take a bus pointer so they can provide appropriate per-bus translated
values to the generic code but that's a more invasive patch. I will
do that in the future, but in the meantime, this fixes the problem
locally

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>