net/mlx5e: Do not rewrite fields with the same match

If we have a match for the same value of a rewrite field, there is no
point for the rewrite. In order to save rewrite actions, and avoid
entirely rewrite actions (if all rewrites are the same), ignore such
rewrite fields.

Signed-off-by: Eli Britstein <elibr@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>