ibm_newemac: Add support for GPCS, SGMII and M88E1112 PHY

Add support for the phy types found on the Arches and other
PowerPC 460 based boards.

Signed-off-by: Victor Gallardo <vgallardo@amcc.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>