pinctrl: nomadik: fix incorrect type in return expression

Sparse reports "warning: incorrect type in return expression (different
address spaces)" because nmk_gpio_populate_chip() is supposed to return
(struct nmk_gpio_chip *) whereas devm_ioremap_resource() returns
(void __iomem *).  ERR_CAST() is needed to fix the warning.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/nomadik/pinctrl-nomadik.c

@@ -1078,7 +1078,7 @@ static struct nmk_gpio_chip *nmk_gpio_populate_chip(struct device_node *np,
 	res = platform_get_resource(gpio_pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(base))
-		return base;
+		return ERR_CAST(base);
 	nmk_chip->addr = base;
 
 	clk = clk_get(&gpio_pdev->dev, NULL);