net/mlx5e: Remove double defined DMAC header re-write element

The firmware DMAC_47_16 header re-write token was defined twice,
clean it up.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reported-by: Jianbo Liu <jianbol@mellanox.com>
Reviewed-by: Jianbo Liu <jianbol@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>