test: l2fwd: add option to give destination MAC
test: l2fwd: add option to give destination MAC

Added option (--dst_addr or -r) to l2fwd that allows the user to specify
what destination MAC addresses to use per port. The MAC addresses are
separated by commas and the number of MAC addresses, if given, must be
equal to the number of interfaces.

This makes it much easier to test l2fwd with TRex, which wants you to have
the MAC address of the destination interface.

Signed-off-by: Juha-Matti Tilli <e80f57da724ae689d53047681b07927adb9737b1@nokia.com>
Reviewed-by: Petri Savolainen <d528fd253b9aaf78fa72edbcc6249e82047f6ce6@nokia.com>
Signed-off-by: Maxim Uvarov <db4d16e02ae2d7493db430203537da8b2e34f290@linaro.org>

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