RDMA/IPoIB: Fix error code return in ipoib_mcast_join

Return the error code in case of ib_sa_join_multicast fail.
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20231121130316.126364-2-jinpu.wang@ionos.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/ulp/ipoib/ipoib_multicast.c

@@ -546,6 +546,7 @@ static int ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast)
 		spin_unlock_irq(&priv->lock);
 		complete(&mcast->done);
 		spin_lock_irq(&priv->lock);
+		return ret;
 	}
 	return 0;
 }