mlx4, mlx5, mthca: Expose max_sge_rd correctly

Applications must not assume that max_sge and max_sge_rd are the same,
Hence expose max_sge_rd correctly as well.

Reported-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mthca/mthca_provider.c

@@ -97,6 +97,7 @@ static int mthca_query_device(struct ib_device *ibdev, struct ib_device_attr *pr
 	props->max_qp              = mdev->limits.num_qps - mdev->limits.reserved_qps;
 	props->max_qp_wr           = mdev->limits.max_wqes;
 	props->max_sge             = mdev->limits.max_sg;
+	props->max_sge_rd          = props->max_sge;
 	props->max_cq              = mdev->limits.num_cqs - mdev->limits.reserved_cqs;
 	props->max_cqe             = mdev->limits.max_cqes;
 	props->max_mr              = mdev->limits.num_mpts - mdev->limits.reserved_mrws;