phy: omap-usb2: invoke pm_runtime_disable on error path

if devm_clk_get for wkupclk fails, there will be an unbalanced
pm_runtime_enable. Fix it here.

Reported-by: Benoit Parrot <[e-mail]>
Cc: Roger Quadros <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

drivers/phy/phy-omap-usb2.c

···
 		phy->wkupclk = devm_clk_get(phy->dev, "usb_phy_cm_clk32k");
 		if (IS_ERR(phy->wkupclk)) {
 			dev_err(&pdev->dev, "unable to get usb_phy_cm_clk32k\n");
+			pm_runtime_disable(phy->dev);
 			return PTR_ERR(phy->wkupclk);
 		} else {
 			dev_warn(&pdev->dev,