ovs: align nlattr properly when needed

I also fix commit 8b32ab9e6ef1: use nla_total_size_64bit() for
OVS_FLOW_ATTR_USED in ovs_flow_cmd_msg_size().

Fixes: 8b32ab9e6ef1 ("ovs: use nla_put_u64_64bit()")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/openvswitch.h

@@ -84,6 +84,7 @@ enum ovs_datapath_attr {
 	OVS_DP_ATTR_STATS,		/* struct ovs_dp_stats */
 	OVS_DP_ATTR_MEGAFLOW_STATS,	/* struct ovs_dp_megaflow_stats */
 	OVS_DP_ATTR_USER_FEATURES,	/* OVS_DP_F_*  */
+	OVS_DP_ATTR_PAD,
 	__OVS_DP_ATTR_MAX
 };
 
@@ -253,6 +254,7 @@ enum ovs_vport_attr {
 	OVS_VPORT_ATTR_UPCALL_PID, /* array of u32 Netlink socket PIDs for */
 				/* receiving upcalls */
 	OVS_VPORT_ATTR_STATS,	/* struct ovs_vport_stats */
+	OVS_VPORT_ATTR_PAD,
 	__OVS_VPORT_ATTR_MAX
 };