test/eventdev: use CPU event type

test/eventdev: use CPU event type

octeontx test application was using non RTE_EVENT_TYPE_CPU
event type to generate the event from CPU.  Upon the introduction
of ethdev Rx adapter, RTE_EVENT_TYPE_ETHDEV has special
meaning. So avoid using non RTE_EVENT_TYPE_CPU event types
to inject events from CPU.

Fixes: d0d654986018 ("net/octeontx: support event Rx adapter")
Cc: stable@dpdk.org
Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Reviewed-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>