xfrm: remove unnecessary check in xfrmi_get_stats64

if tstats of a device is not allocated, this device is not
registered correctly and can not be used.
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/xfrm/xfrm_interface.c

@@ -561,9 +561,6 @@ static void xfrmi_get_stats64(struct net_device *dev,
 {
 	int cpu;
 
-	if (!dev->tstats)
-		return;
-
 	for_each_possible_cpu(cpu) {
 		struct pcpu_sw_netstats *stats;
 		struct pcpu_sw_netstats tmp;