dwc_eth_qos: Add support for Synopsys DWC Ethernet QoS

This patch adds a platform driver for the new generation of the
gigabit ethernet IP from Synopsys. It is developed for version 4.10a
of the IP core.

Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>