spi: release device claimed by bus_find_device_by_name

In success case the function bus_find_device_by_name calls
get_device. In our context put_device should be called to
decrease the device count usage.

Signed-off-by: Roman Tereshonkov <[e-mail]>
Signed-off-by: Grant Likely <[e-mail]>

drivers/spi/spi.c

···
 {
 	static DEFINE_MUTEX(spi_add_lock);
 	struct device *dev = spi->master->dev.parent;
+	struct device *d;
 	int status;
 
 	/* Chipselects are numbered 0..max; validate. */
···
 	 */
 	mutex_lock(&spi_add_lock);
 
-	if (bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev))
-			!= NULL) {
+	d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
+	if (d != NULL) {
 		dev_err(dev, "chipselect %d already in use\n",
 				spi->chip_select);
+		put_device(d);
 		status = -EBUSY;
 		goto done;
 	}