pinctrl: mvebu: make pdma clock on dove mandatory

With the ability to pass clocks through DT, now make the pdma
clock of dove pinctrl mandatory. Otherwise, pinctrl will hang
the system when accessing some registers.
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

drivers/pinctrl/mvebu/pinctrl-dove.c

@@ -595,7 +595,10 @@ static int __devinit dove_pinctrl_probe(struct platform_device *pdev)
 	 * grab clk to make sure it is ticking.
 	 */
 	clk = devm_clk_get(&pdev->dev, NULL);
-	if (!IS_ERR(clk))
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "Unable to get pdma clock");
+		return PTR_RET(clk);
+	}
 	clk_prepare_enable(clk);
 
 	return mvebu_pinctrl_probe(pdev);