net/mlx5: Fix group version management

When adding a rule to a flow group we need increment the version of the
group. Current code fails to do that and as a result, when trying to add
a rule, we will fail to discover a case where an FTE with the same match
value was added while we scanned the groups of the same match criteria,
thus we may try to add an FTE that was already added.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>