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>
diff --git a/drivers/ata/pata_ali.c b/drivers/ata/pata_ali.c
index 7e68edf3..8786455 100644
--- a/drivers/ata/pata_ali.c
+++ b/drivers/ata/pata_ali.c
@@ -295,7 +295,7 @@
 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;
 }