net/kni: fix return value check
net/kni: fix return value check

'rte_kni_release()' return value is not checked, adding it.

Coverity issue: 336837
Fixes: 75e2bc54c018 ("net/kni: add KNI PMD")
Cc: stable@dpdk.org

Signed-off-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

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