Marvell Orion ethernet IP originally is multi-port capable, but SoCs
using the IP usually have multiple single-port controllers built in.
Currently, orion-gbe driver registers each port device with a constant
name, which causes a name conflict with multiple controller instances.

This patch uniquifies port device name generation by prepending
controller's base register address to resolve the name conflict.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>