net: gem: unregister mdio bus if probe fails

If probe fails, the mdio bus isn't unregistered. Fix it.
Signed-off-by: NMichael Walle <michael@walle.cc>
Reviewed-by: NRamon Fried <rfried.dev@gmail.com>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

drivers/net/zynq_gem.c

@@ -711,10 +711,12 @@ static int zynq_gem_probe(struct udevice *dev)
 
 	ret = zynq_phy_init(dev);
 	if (ret)
-		goto err2;
+		goto err3;
 
 	return ret;
 
+err3:
+	mdio_unregister(priv->bus);
 err2:
 	free(priv->rxbuffers);
 err1: