libata: fix kernel-doc parameter warning

Fix libata kernel-doc parameter:

Warning(linux-2.6.25-rc2-git3//drivers/ata/libata-scsi.c:845): No description found for parameter 'rq'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-scsi.c

@@ -828,7 +828,7 @@ static void ata_scsi_sdev_config(struct scsi_device *sdev)
 
 /**
  *	atapi_drain_needed - Check whether data transfer may overflow
- *	@request: request to be checked
+ *	@rq: request to be checked
  *
  *	ATAPI commands which transfer variable length data to host
  *	might overflow due to application error or hardare bug.  This