This patch fixes ovs-dpdk script as options
in DPDK changed and PCI whitelist config changed
from '-w' to '-a' as per [1].

[1] https://github.com/DPDK/dpdk/commit/db27370b57202632ad8830352c1c0ee2dde4542f

Closes-Bug: #2058372
Change-Id: Iae812a4a255c13a42b2d6a691e265922d220f4c8