mrf24j40: Fix en error handling path in 'mrf24j40_probe()'

If this check fails, we must release some resources as done everywhere
else in this function before returning an error code.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Alan Ott <alan@signal11.us>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/mrf24j40.c

@@ -1330,7 +1330,8 @@ static int mrf24j40_probe(struct spi_device *spi)
 	if (spi->max_speed_hz > MAX_SPI_SPEED_HZ) {
 		dev_warn(&spi->dev, "spi clock above possible maximum: %d",
 			 MAX_SPI_SPEED_HZ);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_register_device;
 	}
 
 	ret = mrf24j40_hw_init(devrec);