[POWERPC] fix iSeries PCI resource management

The way iSeries manages PCI IO and Memory resources is a bit strange
and is based on overriding the content of those resources with home
cooked ones afterward.

This changes it a bit to better integrate with the new resource handling
so that the "virtual" tokens that iSeries replaces resources with are
done from the proper per-device fixup hook, and bridge resources are
set to enclose that token space.  This fixes various things such as
the output of /proc/iomem & ioports, among others.  This also fixes up
various boot messages as well.

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