net: dwc_eth_qos: introduce eqos hook eqos_get_enetaddr

i.MX has specific hook to get MAC address, so introduce a hook and move
i.MX code to its own driver

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/drivers/net/dwc_eth_qos.h b/drivers/net/dwc_eth_qos.h
index f470189..b35e774 100644
--- a/drivers/net/dwc_eth_qos.h
+++ b/drivers/net/dwc_eth_qos.h
@@ -240,6 +240,7 @@
 	int (*eqos_calibrate_pads)(struct udevice *dev);
 	int (*eqos_disable_calibration)(struct udevice *dev);
 	int (*eqos_set_tx_clk_speed)(struct udevice *dev);
+	int (*eqos_get_enetaddr)(struct udevice *dev);
 	ulong (*eqos_get_tick_clk_rate)(struct udevice *dev);
 };