examples/vhost: use factorized default Rx/Tx configuration
examples/vhost: use factorized default Rx/Tx configuration

Refer to Pablo's commit (81f7ecd934372fc):
    "use factorized default Rx/Tx configuration

    For apps that were using default rte_eth_rxconf and rte_eth_txconf
    structures, these have been removed and now they are obtained by
    calling rte_eth_dev_info_get, just before setting up RX/TX queues."

Move zero copy's deferred start set up ahead.

Signed-off-by: Huawei Xie <3b3be4428106761300a2ee559c9f71ecdb091553@intel.com>

phermansson/dpdk,phermansson/dpdk,phermansson/dpdk,phermansson/dpdk