gpio: mb86s7x: Handle return value of clk_prepare_enable.

clk_prepare_enable() can fail here and we must check its return value.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-mb86s7x.c

@@ -168,7 +168,9 @@ static int mb86s70_gpio_probe(struct platform_device *pdev)
 	if (IS_ERR(gchip->clk))
 		return PTR_ERR(gchip->clk);
 
-	clk_prepare_enable(gchip->clk);
+	ret = clk_prepare_enable(gchip->clk);
+	if (ret)
+		return ret;
 
 	spin_lock_init(&gchip->lock);