rockchip: gpio: remove dead code

In the following statements
if (a) return a; if (a) return c;
the second return can never be executed.

Identified by cppcheck.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

drivers/gpio/rk_gpio.c

@@ -86,10 +86,6 @@ static int rockchip_gpio_get_function(struct udevice *dev, unsigned offset)
 	ret = pinctrl_get_gpio_mux(priv->pinctrl, priv->bank, offset);
 	if (ret)
 		return ret;
-
-	/* If it's not 0, then it is not a GPIO */
-	if (ret)
-		return GPIOF_FUNC;
 	is_output = readl(&regs->swport_ddr) & OFFSET_TO_BIT(offset);
 
 	return is_output ? GPIOF_OUTPUT : GPIOF_INPUT;