net/mlx5e: E-Switch, Specify flow_source for rule with no in_port

The flow_source must be specified, even for rule without matching
source vport, because some actions are only allowed in uplink.
Otherwise, rule can't be offloaded and firmware syndrome happens.

Fixes: 6fb0701a9cfa ("net/mlx5: E-Switch, Add support for offloading rules with no in_port")
Signed-off-by: Jianbo Liu <jianbol@mellanox.com>
Reviewed-by: Chris Mi <chrism@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>