IB/mlx5: Fix RSS Toeplitz setup to be aligned with the HW specification

commit b7165bd0d6cbb93732559be6ea8774653b204480 upstream.

The specification for the Toeplitz function doesn't require to set the key
explicitly to be symmetric. In case a symmetric functionality is required
a symmetric key can be simply used.

Wrongly forcing the algorithm to symmetric causes the wrong packet
distribution and a performance degradation.

Link: https://lore.kernel.org/r/[email protected]
Cc: <[email protected]> # 4.7
Fixes: 28d6137 ("IB/mlx5: Add RSS QP support")
Signed-off-by: Yishai Hadas <[email protected]>
Reviewed-by: Alex Vainman <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/infiniband/hw/mlx5/qp.c

@@ -1501,7 +1501,6 @@ static int create_rss_raw_qp_tir(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp,
 		}
 
 		MLX5_SET(tirc, tirc, rx_hash_fn, MLX5_RX_HASH_FN_TOEPLITZ);
-		MLX5_SET(tirc, tirc, rx_hash_symmetric, 1);
 		memcpy(rss_key, ucmd.rx_hash_key, len);
 		break;
 	}