examples/flow_filtering: add flow director config for i40e
examples/flow_filtering: add flow director config for i40e

Rte_fdir_conf of rte_eth_conf should be initialized before
port initialization. It is a workaround solution when working
with Intel I40e.

Fixes: 4a3ef59a10c8 ("examples/flow_filtering: add simple demo of flow API")
Cc: stable@dpdk.org

Signed-off-by: Rosen Xu <8f603db01337dbfe2ce4743ebc0cdbcec6fa456f@intel.com>
Acked-by: Ori Kam <dd654df5de18ba542acfaea52fe1a0799392087d@mellanox.com>
Reviewed-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk