net/mlx5: validate ethernet type on E-Switch

net/mlx5: validate ethernet type on E-Switch

This patch updates the validation routine for the E-Switch Flows.
The ethernet type field can be specified within inner and outer
tunnel ethernet items, by vlan item or implicitly deduced from
IP address items. The validation routine checks all these items
and their combinations for mutual compatibility issues and possible
conflicts.

Cc: stable@dpdk.org
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>