mdio-gpio: Add mdc pin direction initialization

mdc pin should always be output. Initialize it as output,
so each board code does not need to do this.

Signed-off-by: Paulius Zaleckas <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/phy/mdio-gpio.c

···
 	if (gpio_request(bitbang->mdio, "mdio"))
 		goto out_free_mdc;
 
+	gpio_direction_output(bitbang->mdc, 0);
+
 	dev_set_drvdata(dev, new_bus);
 
 	ret = mdiobus_register(new_bus);