test: l2fwd: added poll queue mode
test: l2fwd: added poll queue mode

Added poll queue mode (mode == 4), which uses poll type queues
for packet input. Configuration and functionality is very similar
to direct recv mode.

Signed-off-by: Petri Savolainen <d528fd253b9aaf78fa72edbcc6249e82047f6ce6@nokia.com>
Reviewed-and-tested-by: Stuart Haslam <1fce01f364ef5298e64e07a42e08efeef153fa98@linaro.org>
Signed-off-by: Maxim Uvarov <db4d16e02ae2d7493db430203537da8b2e34f290@linaro.org>

mike-holmes-linaro/odp,nmorey/odp,dkrot/odp,mike-holmes-linaro/odp,ravineet-singh/odp,ravineet-singh/odp,dkrot/odp,erachmi/odp,erachmi/odp,mike-holmes-linaro/odp,ravineet-singh/odp,nmorey/odp,dkrot/odp,nmorey/odp,mike-holmes-linaro/odp,erachmi/odp,dkrot/odp,nmorey/odp,ravineet-singh/odp,erachmi/odp