net/mlx5e: Fix no rewrite fields with the same match

With commit 27c11b6b ("net/mlx5e: Do not rewrite fields with the
same match") there are no rewrites if the rewrite value is the same as
the matched value. However, if the field is not matched, the rewrite is
also wrongly skipped. Fix it.

Fixes: 27c11b6b ("net/mlx5e: Do not rewrite fields with the same match")
Signed-off-by: Eli Britstein <elibr@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>