gpio: omap : Add missing clk_unprepare().

omap_gpio_probe() can fail here and we must disable clock.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-omap.c

@@ -1247,6 +1247,8 @@ static int omap_gpio_probe(struct platform_device *pdev)
 	if (ret) {
 		pm_runtime_put_sync(dev);
 		pm_runtime_disable(dev);
+		if (bank->dbck_flag)
+			clk_unprepare(bank->dbck);
 		return ret;
 	}