openvswitch: Use generic struct pcpu_tstats.

Rather than defining ovs specific stats struct (vport_percpu_stats),
we can use existing pcpu_tstats to achieve exactly same functionality.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

diff --cc net/openvswitch/vport.c
Simple merge

diff --cc net/openvswitch/vport.h
Simple merge