kni: fix build with kernel < 2.6.34
kni: fix build with kernel < 2.6.34

Signed-off-by: Ivan Boule <8408c61bea57ac94dd0d4dac44b115be1b288952@6wind.com>
Acked-by: Thomas Monjalon <ee2fa8b2681c737f775687e475dcbf2028a412f1@6wind.com>

john-mcnamara-intel/dpdk,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk,mixja/dpdk,msune/dpdk,msune/dpdk,mixja/dpdk,john-mcnamara-intel/dpdk,tsphillips/dpdk-fork,venkynv/dpdk-mirror,tsphillips/dpdk-fork,venkynv/dpdk-mirror,mixja/dpdk,venkynv/dpdk-mirror,mixja/dpdk,tsphillips/dpdk-fork,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,msune/dpdk,msune/dpdk