gpio: omap : Add missing clk_unprepare().

omap_gpio_probe() can fail here and we must disable clock.

Signed-off-by: Arvind Yadav <[e-mail]>
Reviewed-by: Grygorii Strashko <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpio-omap.c

···
 	if (ret) {
 		pm_runtime_put_sync(dev);
 		pm_runtime_disable(dev);
+		if (bank->dbck_flag)
+			clk_unprepare(bank->dbck);
 		return ret;
 	}