ide: convert "empty" REQ_TYPE_ATA_CMD requests to use REQ_TYPE_ATA_TASKFILE

Based on the previous work by Tejun Heo.

There should be no functionality changes caused by this patch.

Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 446b128..97894ab 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -880,7 +880,7 @@
 		return -EBUSY;
 
 	ide_init_drive_cmd(&rq);
-	rq.cmd_type = REQ_TYPE_ATA_CMD;
+	rq.cmd_type = REQ_TYPE_ATA_TASKFILE;
 
 	drive->tune_req = (u8) arg;
 	drive->special.b.set_tune = 1;