sc16is7xx: null ptr check

If a wrong compatible flag in specified, the of_match_device
returning null.
Implemented check and if NULL then returning -ENODEV.
Signed-off-by: NSean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sc16is7xx.c

@@ -1321,6 +1321,9 @@ static int sc16is7xx_spi_probe(struct spi_device *spi)
 		const struct of_device_id *of_id =
 			of_match_device(sc16is7xx_dt_ids, &spi->dev);
 
+		if (!of_id)
+			return -ENODEV;
+
 		devtype = (struct sc16is7xx_devtype *)of_id->data;
 	} else {
 		const struct spi_device_id *id_entry = spi_get_device_id(spi);
@@ -1380,6 +1383,9 @@ static int sc16is7xx_i2c_probe(struct i2c_client *i2c,
 		const struct of_device_id *of_id =
 				of_match_device(sc16is7xx_dt_ids, &i2c->dev);
 
+		if (!of_id)
+			return -ENODEV;
+
 		devtype = (struct sc16is7xx_devtype *)of_id->data;
 	} else {
 		devtype = (struct sc16is7xx_devtype *)id->driver_data;