rbd: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO

This patch fixes coccinelle error regarding usage of IS_ERR and
PTR_ERR instead of PTR_ERR_OR_ZERO.

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>

drivers/block/rbd.c

@@ -4752,7 +4752,7 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
 
 		image_id = ceph_extract_encoded_string(&p, p + ret,
 						NULL, GFP_NOIO);
-		ret = IS_ERR(image_id) ? PTR_ERR(image_id) : 0;
+		ret = PTR_ERR_OR_ZERO(image_id);
 		if (!ret)
 			rbd_dev->image_format = 2;
 	} else {