patches: enable DPDK memif client zero-copy in VPP

This is a VPP patch to enable DPDK memif interface in
client role to send and receive packets in zero-copy method.

Signed-off-by: Liangxing Wang <liangxing.wang@arm.com>
Reviewed-by: Nathan Brown <nathan.brown@arm.com>
Change-Id: I594bd2c3fef71dfe2133afd2266324b77051796c