net/mlx5: Kconfig: Fix spelling typo

"mdoe"->"mode"

Fixes: d956873f ("net/mlx5e: Introduce kconfig var for TC support")
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reported-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>