[POWERPC] 4xx: Change Kilauea dts to support new EMAC device tree properties

The recent changes from Benjamin Herrenschmidt to the ibm_newemac now
make it possible to support other 4xx variants by just defining the
correct properties in the device tree. In this case of the 405EX we
need to define "has-mdio" in the RGMII node and "has-inverted-stacr-oc"
and "has-new-stacr-staopc" in the EMAC node same as on the 440EPx.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>