kni: fix build with kernel 4.9

kni: fix build with kernel 4.9

compile error:
  CC [M]  .../lib/librte_eal/linuxapp/kni/igb_main.o
.../lib/librte_eal/linuxapp/kni/igb_main.c:2317:21:
error: initialization from incompatible pointer type
	[-Werror=incompatible-pointer-types]
  .ndo_set_vf_vlan = igb_ndo_set_vf_vlan,
                     ^~~~~~~~~~~~~~~~~~~

Linux kernel 4.9 updates API for ndo_set_vf_vlan:
Linux: 79aab093a0b5 ("net: Update API for VF vlan protocol 802.1ad support")

Use new API for Linux kernels >= 4.9

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Tested-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>