net: openvswitch: Add support to count upcall packets

Add support to count upall packets, when kmod of openvswitch
upcall to count the number of packets for upcall succeed and
failed, which is a better way to see how many packets upcalled
on every interfaces.

Signed-off-by: wangchuanlei <wangchuanlei@inspur.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>