This adds device tree support to the davinci-emac driver.

This needs some changes to the driver as the device has four different
resources. Three of them are merged into a single resource in the
dts files with the node providing offsets for the different resources
to base address. The mdio node is found separately in the dts, so we
have to split this out to a different driver. Since this driver has been
unused previously, we do not bother maintaining two different probe
methods and remove platform probe support at the same time.

Signed-off-by: Heinrich Toews <heinrich.toews@wago.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>