examples/ipsec-secgw: add event port-lcore link

examples/ipsec-secgw: add event port-lcore link

Add event device port-lcore link and specify which event queues should
be connected to the event port. Generate a default config for event
port-lcore links if it is not specified in the configuration. This
routine will check the number of available ports and then create links
according to the number of cores available. This patch also adds a new
entry in the eventmode conf to denote that all queues are to be linked
with every port. This enables one core to receive packets from all
ethernet ports.

Signed-off-by: Anoob Joseph <anoobj@marvell.com>
Signed-off-by: Lukasz Bartosik <lbartosik@marvell.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Acked-by: Akhil Goyal <akhil.goyal@nxp.com>