net: gemini: add missed free_netdev

This driver forgets to free allocated netdev in remove like
what is done in probe failure.
Add the free to fix it.
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cortina/gemini.c

@@ -2524,6 +2524,7 @@ static int gemini_ethernet_port_remove(struct platform_device *pdev)
 	struct gemini_ethernet_port *port = platform_get_drvdata(pdev);
 
 	gemini_port_remove(port);
+	free_netdev(port->netdev);
 	return 0;
 }