openvswitch: Move mega-flow list out of rehashing struct.

ovs-flow rehash does not touch mega flow list. Following patch
moves it dp struct datapath.  Avoid one extra indirection for
accessing mega-flow list head on every packet receive.

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

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

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

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

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