net/mlx5: remove self-assignment on esw->dev

There is a self assignment of esw->dev to itself, clean this up by
removing it. Also make dev a const pointer.

Addresses-Coverity: ("Self assignment")
Fixes: 6cedde45 ("net/mlx5: E-Switch, Verify support QoS element type")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/eswitch.c

@@ -1413,7 +1413,7 @@ static int esw_vport_egress_config(struct mlx5_eswitch *esw,
 
 static bool element_type_supported(struct mlx5_eswitch *esw, int type)
 {
-	struct mlx5_core_dev *dev = esw->dev = esw->dev;
+	const struct mlx5_core_dev *dev = esw->dev;
 
 	switch (type) {
 	case SCHEDULING_CONTEXT_ELEMENT_TYPE_TSAR: