net/mlx5: add metadata register copy table

net/mlx5: add metadata register copy table

While reg_c[meta] can be copied to reg_b simply by modify-header
action (it is supported by hardware), it is not possible to copy
reg_c[mark] to the STE flow_tag as flow_tag is not a metadata
register and this is not supported by hardware. Instead, it
should be manually set by a flow per each unique MARK ID. For
this purpose, there should be a dedicated flow table -
RX_CP_TBL and all the Rx flow should pass by the table
to properly copy values from the register to flow tag field.

And for each MARK action, a copy flow should be added
to RX_CP_TBL according to the MARK ID like:
  (if reg_c[mark] == mark_id),
    flow_tag := mark_id / reg_b := reg_c[meta] / jump to RX_ACT_TBL

For SET_META action, there can be only one default flow like:
  reg_b := reg_c[meta] / jump to RX_ACT_TBL

Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>