IB/mlx5: Refactor CQE compression response

Refactor CQE compression response to be fully set only
when it`s really supported. There is no change from user
perspective because anyway resp.cqe_comp_caps.max_num was
set to zero.
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Yonatan Cohen <yonatanc@mellanox.com>W
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -983,13 +983,17 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
 	}
 
 	if (field_avail(typeof(resp), cqe_comp_caps, uhw->outlen)) {
+		resp.response_length += sizeof(resp.cqe_comp_caps);
+
+		if (MLX5_CAP_GEN(dev->mdev, cqe_compression)) {
 			resp.cqe_comp_caps.max_num =
-			MLX5_CAP_GEN(dev->mdev, cqe_compression) ?
-			MLX5_CAP_GEN(dev->mdev, cqe_compression_max_num) : 0;
+				MLX5_CAP_GEN(dev->mdev,
+					     cqe_compression_max_num);
+
 			resp.cqe_comp_caps.supported_format =
 				MLX5_IB_CQE_RES_FORMAT_HASH |
 				MLX5_IB_CQE_RES_FORMAT_CSUM;
-		resp.response_length += sizeof(resp.cqe_comp_caps);
+		}
 	}
 
 	if (field_avail(typeof(resp), packet_pacing_caps, uhw->outlen) &&