netdev-linux: remove sum of vport stats and kernel netdev stats.

When using kernel veth as OVS interface, doubled drop counter
value is shown when veth drops packets due to traffic overrun.

In netdev_linux_get_stats, it reads both vport stats and kernel
netdev stats, in case vport stats retrieve failure. If both of
them success, error counters are added to include errors from
different layers. But implementation of ovs_vport_get_stats in
kernel data path has included kernel netdev stats by calling
dev_get_stats. When drop or other error counters is not zero,
its value is doubled by netdev_linux_get_stats.

In this change, adding kernel netdev stats into vport stats
is removed, since vport stats includes all information of
kernel netdev stats.

Signed-off-by: Jiang Lidong <jianglidong3@jd.com>
Signed-off-by: William Tu <u9012063@gmail.com>

lib/netdev-linux.c

@@ -2208,18 +2208,6 @@ netdev_linux_get_stats(const struct netdev *netdev_,
         /* stats not available from OVS then use netdev stats. */
         *stats = dev_stats;
     } else {
-        /* Use kernel netdev's packet and byte counts since vport's counters
-         * do not reflect packet counts on the wire when GSO, TSO or GRO are
-         * enabled. */
-        stats->rx_packets = dev_stats.rx_packets;
-        stats->rx_bytes = dev_stats.rx_bytes;
-        stats->tx_packets = dev_stats.tx_packets;
-        stats->tx_bytes = dev_stats.tx_bytes;
-
-        stats->rx_errors           += dev_stats.rx_errors;
-        stats->tx_errors           += dev_stats.tx_errors;
-        stats->rx_dropped          += dev_stats.rx_dropped;
-        stats->tx_dropped          += dev_stats.tx_dropped;
         stats->multicast           += dev_stats.multicast;
         stats->collisions          += dev_stats.collisions;
         stats->rx_length_errors    += dev_stats.rx_length_errors;