net/mlx4_en: fix a memory leak bug

In mlx4_en_config_rss_steer(), 'rss_map->indir_qp' is allocated through
kzalloc(). After that, mlx4_qp_alloc() is invoked to configure RSS
indirection. However, if mlx4_qp_alloc() fails, the allocated
'rss_map->indir_qp' is not deallocated, leading to a memory leak bug.

To fix the above issue, add the 'qp_alloc_err' label to free
'rss_map->indir_qp'.

Fixes: 4931c6ef04 ("net/mlx4_en: Optimized single ring steering")
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

drivers/net/ethernet/mellanox/mlx4/en_rx.c

@@ -1187,7 +1187,7 @@ int mlx4_en_config_rss_steer(struct mlx4_en_priv *priv)
 	err = mlx4_qp_alloc(mdev->dev, priv->base_qpn, rss_map->indir_qp);
 	if (err) {
 		en_err(priv, "Failed to allocate RSS indirection QP\n");
-		goto rss_err;
+		goto qp_alloc_err;
 	}
 
 	rss_map->indir_qp->event = mlx4_en_sqp_event;
@@ -1241,6 +1241,7 @@ indir_err:
 		       MLX4_QP_STATE_RST, NULL, 0, 0, rss_map->indir_qp);
 	mlx4_qp_remove(mdev->dev, rss_map->indir_qp);
 	mlx4_qp_free(mdev->dev, rss_map->indir_qp);
+qp_alloc_err:
 	kfree(rss_map->indir_qp);
 	rss_map->indir_qp = NULL;
 rss_err: