Check input argument "rte_eth_dev *ethdev", to be sure variable is not
NULL before operating on it.
Coverity issue: 337922
Fixes: 70d6b7f550 ("net/ipn3ke: add representor")
Cc: stable@dpdk.org
Signed-off-by: Andy Pei <andy.pei@intel.com>
Acked-by: Rosen Xu <rosen.xu@intel.com>