datapath: Fix Frame-size larger than 1024 bytes warning.

datapath: Fix Frame-size larger than 1024 bytes warning.

Upstream commit:
    commit 190aa3e77880a05332ea1ccb382a51285d57adb5
    Author: pravin shelar <pshelar@ovn.org>
    Date:   Mon Sep 19 13:50:59 2016 -0700

    openvswitch: Fix Frame-size larger than 1024 bytes warning.

    There is no need to declare separate key on stack,
    we can just use sw_flow->key to store the key directly.

    This commit fixes following warning:

    net/openvswitch/datapath.c: In function ‘ovs_flow_cmd_new’:
    net/openvswitch/datapath.c:1080:1: warning: the frame size of 1040 bytes
    is larger than 1024 bytes [-Wframe-larger-than=]

    Signed-off-by: Pravin B Shelar <pshelar@ovn.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Signed-off-by: Joe Stringer <joe@ovn.org>