net/mlx5: support e-switch TCP-flags flow filter

net/mlx5: support e-switch TCP-flags flow filter

This patch adds support for offloading flow rules with TCP-flags
filter to mlx5 eswitch Hardwrae.

With mlx5 it is possible to offload a limited set of flow rules to
the mlxsw (or e-switch) using the DPDK flow commands using the
"transfer" attribute. This set of flow rules also supports filtering
according to the values found in the TCP flags.
This patch implements this offload capability in the mlx5 PMD under
transfer attribute.

Signed-off-by: Moti Haimovsky <motih@mellanox.com>