net/mlx5: fix metadata split with encap action

net/mlx5: fix metadata split with encap action

In order to move the mbuf metadata from the WQE to the FDB steering
domain, the PMD add for each NIC TX flow a new action to copy the
metadata register REG_A to REG_C_0.

This copy action is considered as modify header action from HW
perspective.

The HW doesn't support to do modify header action after ant
encapsulation action.

The split metadata function wrongly added the copy action in the end of
the original actions list, hence, NIC egress flow with encapsulation
action failed when the PMD worked with dv_xmeta_en mode.

Move the copy action to be before and back to back with the
encapsulation action for the aforementioned case.

Fixes: 71e254bc0294 ("net/mlx5: split Rx flows to provide metadata copy")
Cc: stable@dpdk.org
Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>