[SPARC64]: Temporary workaround for PCI-E slot on T1000.

The PCI-E slot on T1000 connects directly to the Fire PCI chip with no
intervening bridges visible in the OBP tree.

Unfortunately the bus numbering of the device in that slot is
different (2) from the PCI host controller (0), and thus the
pci_bus_{read,write}_config_*() calls don't work out.

Complicating things further the Fire PCI controller has no config
space it responds to either.

For now treat this case specially so that devices in the slot work.

Longer term we need to perhaps cons up a dummy bridge between the Fire
and the PCI-E slot so that the bus hierarchy is complete inside of the
kernel and thus the bus numbering all works out right.

Signed-off-by: David S. Miller <davem@davemloft.net>