[POWERPC] Fix problems with device tree representation of TSI-1xx bridges

[POWERPC] Fix problems with device tree representation of TSI-1xx bridges

This fixes some problems with the way the some things
represented in the device tree for the Holly and Taiga boards.  This
means changes both to the dts files, and to the code which
instantiates the tsi108 ethernet platform devices based on the device
tree.

	- First, and most importantly, the ethernet PHYs are given
with an identical 'reg' property.  This reg currently encodes the
accessible register used to initiate mdio interaction with the PHYs,
rather than a meaningful address on the parent bus (mdio in this
case), which is incorrect.  Instead we give the address of these
registers as 'reg' in the mdio node itself, and encode the ID of each
phy in their 'reg' propertyies.
	- Currently the platform device constructor enables a
workaround in the tsi108 ethernet driver based on the compatible
property of the PHY.  This is incorrect, because the workaround in
question is necessary due to the board's wiring of the PHY, not the
model of PHY itself.  This patch alters the constructor to instead
enable the workaround based on a new special property in the PHY node.
	- The compatible properties on a number of nodes in the device
tree are insufficiently precise.  In particular the PHYs give only
"bcm54xx", which is broken, since there are many bcm54xx PHY models,
and they have differences which matter.  The mdio had a compatible
property of "tsi-ethernet" identical to the ethernet MAC nodes, which
doesn't make sense.  The ethernet, i2c, bridge and PCI nodes were
given only as "tsi-*" which is somewhat inprecise, we replace with
"tsi108-*" in the case of Taiga (which has a TSI108 bridge), and
"tsi109-*", "tsi108-*" in the case of Holly (which has a TSI109
bridge).
	- We remove some "model" properties from the ethernets on
Taiga board which were neither useful nor adequately precise.
	- On Holly we change to using a dtc label instead of a full
path to reference the MPIC node, which makes the dts a little more
readable.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>