serial: max310x: Set IRQF_TRIGGER_FALLING flag when dev.of_node is not NULL

When dev.of_node is not NULL, we also need to set IRQF_TRIGGER_FALLING
flag, otherwise it may cause uncertain interrupts.
Signed-off-by: Liu Xiang <liu.xiang6@zte.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/max310x.c

@@ -1329,9 +1329,9 @@ static int max310x_spi_probe(struct spi_device *spi)
 		const struct spi_device_id *id_entry = spi_get_device_id(spi);
 
 		devtype = (struct max310x_devtype *)id_entry->driver_data;
-		flags = IRQF_TRIGGER_FALLING;
 	}
 
+	flags = IRQF_TRIGGER_FALLING;
 	regcfg.max_register = devtype->nr * 0x20 - 1;
 	regmap = devm_regmap_init_spi(spi, &regcfg);