net/mlx5e: Obsolete param field holding a constant value

The LRO WQE size is a constant, obsolete the parameter field
that holds it.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Reviewed-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>