Currently, user could use runtime config "rx_func_hint=simple" to
select the hns3_recv_pkts API, but the API's name get from
rte_eth_rx_burst_mode_get is "Scalar" which has not reflected "simple".
So this patch renames hns3_recv_pkts to hns3_recv_pkts_simple, and
also change it's name which gets from rte_eth_rx_burst_mode_get to
"Scalar Simple" to maintain conceptual consistency.