xfrm: use new function dev_fetch_sw_netstats

static void xfrmi_get_stats64(struct net_device *dev,

			       struct rtnl_link_stats64 *s)

{

	int cpu;

	for_each_possible_cpu(cpu) {

		struct pcpu_sw_netstats *stats;

		struct pcpu_sw_netstats tmp;

		int start;

		stats = per_cpu_ptr(dev->tstats, cpu);

		do {

			start = u64_stats_fetch_begin_irq(&stats->syncp);

			tmp.rx_packets = stats->rx_packets;

			tmp.rx_bytes   = stats->rx_bytes;

			tmp.tx_packets = stats->tx_packets;

			tmp.tx_bytes   = stats->tx_bytes;

		} while (u64_stats_fetch_retry_irq(&stats->syncp, start));

		s->rx_packets += tmp.rx_packets;

		s->rx_bytes   += tmp.rx_bytes;

		s->tx_packets += tmp.tx_packets;

		s->tx_bytes   += tmp.tx_bytes;

	}

	dev_fetch_sw_netstats(s, dev->tstats);

	s->rx_dropped = dev->stats.rx_dropped;

	s->tx_dropped = dev->stats.tx_dropped;