RDMA/hns: Fix unnecessary err return when using invalid congest control algorithm

Add a default congest control algorithm so that driver won't return
an error when the configured algorithm is invalid.

Fixes: f91696f2 ("RDMA/hns: Support congestion control type selection according to the FW")
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://lore.kernel.org/r/20231028093242.670325-1-huangjunxian6@hisilicon.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -4760,10 +4760,15 @@ static int check_cong_type(struct ib_qp *ibqp,
 		cong_alg->wnd_mode_sel = WND_LIMIT;
 		break;
 	default:
-		ibdev_err(&hr_dev->ib_dev,
-			  "error type(%u) for congestion selection.\n",
-			  hr_dev->caps.cong_type);
-		return -EINVAL;
+		ibdev_warn(&hr_dev->ib_dev,
+			   "invalid type(%u) for congestion selection.\n",
+			   hr_dev->caps.cong_type);
+		hr_dev->caps.cong_type = CONG_TYPE_DCQCN;
+		cong_alg->alg_sel = CONG_DCQCN;
+		cong_alg->alg_sub_sel = UNSUPPORT_CONG_LEVEL;
+		cong_alg->dip_vld = DIP_INVALID;
+		cong_alg->wnd_mode_sel = WND_LIMIT;
+		break;
 	}
 
 	return 0;