serial: max310x: Unprepare and disable clock in error path

In one error case the clock may be left prepared and enabled.
Unprepare and disable clock in that case to balance state of
the hardware.

Fixes: d4d6f03c ("serial: max310x: Try to get crystal clock rate from property")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210625153733.12911-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/max310x.c

@@ -1293,7 +1293,8 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty
 		freq = uartclk;
 	if (freq == 0) {
 		dev_err(dev, "Cannot get clock rate\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out_clk;
 	}
 
 	if (xtal) {