drivers: use req op accessor

The req operation REQ_OP is separated from the rq_flag_bits
definition. This converts the block layer drivers to
use req_op to get the op from the request struct.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 81666a5..4506620 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3286,9 +3286,9 @@
 		goto err;
 	}
 
-	if (rq->cmd_flags & REQ_DISCARD)
+	if (req_op(rq) == REQ_OP_DISCARD)
 		op_type = OBJ_OP_DISCARD;
-	else if (rq->cmd_flags & REQ_WRITE)
+	else if (req_op(rq) == REQ_OP_WRITE)
 		op_type = OBJ_OP_WRITE;
 	else
 		op_type = OBJ_OP_READ;