ide: don't abuse cmd_type

Currently the legacy ide driver defines several request types of it's own,
which is in the way of removing that field entirely.

Instead add a type field to struct ide_request and use that to distinguish
the different types of IDE-internal requests.

It's a bit of a mess, but so is the surrounding code..

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/ide/ide-taskfile.c

@@ -432,7 +432,8 @@ int ide_raw_taskfile(ide_drive_t *drive, struct ide_cmd *cmd, u8 *buf,
 
 	rq = blk_get_request(drive->queue, rw, __GFP_RECLAIM);
 	scsi_req_init(rq);
-	rq->cmd_type = REQ_TYPE_ATA_TASKFILE;
+	rq->cmd_type = REQ_TYPE_DRV_PRIV;
+	ide_req(rq)->type = ATA_PRIV_TASKFILE;
 
 	/*
 	 * (ks) We transfer currently only whole sectors.