pata_ali: use atapi_cmd_type() to determine cmd type instead of transfer size

pata_ali was using qc->nbytes to determine whether a command is
data transfer type or not.  As now qc->nbytes can be extended by
padding and draining buffers, these tests are not useful anymore.

Use atapi_cmd_type() instead.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/pata_ali.c

@@ -295,7 +295,7 @@ static void ali_lock_sectors(struct ata_device *adev)
 static int ali_check_atapi_dma(struct ata_queued_cmd *qc)
 {
 	/* If its not a media command, its not worth it */
-	if (qc->nbytes < 2048)
+	if (atapi_cmd_type(qc->cdb[0]) == ATAPI_MISC)
 		return -EOPNOTSUPP;
 	return 0;
 }