kni: fix not contiguous FIFO

kni: fix not contiguous FIFO

KNI requires FIFO to be physically contiguous, with existing
'rte_memzone_reserve()' API this is not guaranteed by default and as a
result KNI rings and packet delivery may be broken if reserved memory
is not physically contiguous.

Fixing it by providing 'RTE_MEMZONE_IOVA_CONTIG' flag to ask physically
contiguous memory.

Bugzilla ID: 389
Fixes: 23fa86e529e4 ("memzone: enable IOVA-contiguous reserving")
Cc: stable@dpdk.org
Signed-off-by: Scott Wasson <scott_wasson@affirmednetworks.com>
Acked-by: Ferruh Yigit <ferruh.yigit@intel.com>