IB/ipoib: Fix CONFIG_INFINIBAND_IPOIB_CM

commit efc1eedb upstream.

If the above is turned off then ipoib_cm_dev_init unconditionally
returns ENOSYS, and the newly added error handling in
0b3957 prevents ipoib from coming up at all:

kernel: mlx4_0: ipoib_transport_dev_init failed
kernel: mlx4_0: failed to initialize port 1 (ret = -12)

Fixes: 0b39578b (IB/ipoib: Use dedicated workqueues per interface)
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/infiniband/ulp/ipoib/ipoib_verbs.c

@@ -176,7 +176,8 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
 		else
 			size += ipoib_recvq_size * ipoib_max_conn_qp;
 	} else
-		goto out_free_wq;
+		if (ret != -ENOSYS)
+			goto out_free_wq;
 
 	priv->recv_cq = ib_create_cq(priv->ca, ipoib_ib_completion, NULL, dev, size, 0);
 	if (IS_ERR(priv->recv_cq)) {