ide: don't use req->special

Just replace it with a field of the same name in struct ide_req.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 34c1165..db1a65f 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -639,7 +639,7 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 		goto out;
 	}
 	if (req->cmd[13] & REQ_IDETAPE_PC1) {
-		pc = (struct ide_atapi_pc *)rq->special;
+		pc = (struct ide_atapi_pc *)ide_req(rq)->special;
 		req->cmd[13] &= ~(REQ_IDETAPE_PC1);
 		req->cmd[13] |= REQ_IDETAPE_PC2;
 		goto out;