net/mlx5: DR, Support SW created encap actions for FW table

In some cases, steering might need to use SW-created action in
FW table, which results in wrong packet reformat being used:

  mlx5_core 0000:81:00.1: mlx5_cmd_check:756:(pid 1154):
      SET_FLOW_TABLE_ENTRY(0×936) op_mod(0×0) failed,
      status bad resource(0×5), syndrome (0xf2ff71)

This patch adds support for usage of SW-created packet reformat (encap)
actions in FW tables, and adds clear error flow for attempt to use
SW-created modify header on FW tables.

Fixes: 6a48faee

 ("net/mlx5: Add direct rule fs_cmd implementation")
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Erez Shitrit <erezsh@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>