[POWERPC] efika: add phy-handle property for fec_mpc52xx

The new network driver fec_mpc52xx will not work on efika because the
firmware does not provide all required properties.
http://www.powerdeveloper.org/asset/by-id/46 has a Forth script to
create more properties. But only the phy stuff is required to get a
working network.

This should go into the kernel because its appearently
impossible to boot the script via tftp and then load the real boot
binary (yaboot or zimage).

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>