[PATCH] powerpc: Recognize /chaos bridge on old pmacs as PCI

The first generation of PCI powermacs had a host bridge called /chaos
which was for all intents and purposes a PCI host bridge, but has a
device_type of "vci" in the device tree (presumably it's not really
PCI at the hardware level or something).

The OF parsing stuff in arch/powerpc/kernel/prom_parse.c currently
doesn't recognize it as a PCI bridge, which means that controlfb.c
can't get its device addresses.

This makes prom_parse.c recognize a device_type of "vci" as indicating
a PCI host bridge.  With this, controlfb works again.

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>