[SCSI] scsi_transport_spi: fix for unbalanced reference counting

Check the domain validation flag on the given device before referencing
scsi_device instance, otherwise if the flag is already set we return without
decrementing the reference count.

Signed-off-by: Mike Maslenkin <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/scsi_transport_spi.c

···
 	u8 *buffer;
 	const int len = SPI_MAX_ECHO_BUFFER_SIZE*2;
 
-	if (unlikely(scsi_device_get(sdev)))
+	if (unlikely(spi_dv_in_progress(starget)))
 		return;
 
-	if (unlikely(spi_dv_in_progress(starget)))
+	if (unlikely(scsi_device_get(sdev)))
 		return;
 	spi_dv_in_progress(starget) = 1;