On the root PCI bus, the OBP device tree lists device 3 twice.
Once as 'pm' and once as 'lomp'.
Everything goes downhill from there.
Ignore the second instance to workaround this.
Thanks to Kövedi_Krisztián for the bug report and
testing the fix.
Signed-off-by: David S. Miller <davem@davemloft.net>