Report error message if clearing O_NONBLOCK flag will fail,
then return from function.
Coverity issue: 143439
Fixes: ef53b6030039 ("net/virtio-user: support LSC")
Cc: stable@dpdk.org
Signed-off-by: Sebastian Basierski <sebastianx.basierski@intel.com>
Acked-by: Jianfeng Tan <jianfeng.tan@intel.com>
Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>