gtp: use skb_dst_update_pmtu_no_confirm() instead of direct call

skb_dst_update_pmtu_no_confirm() is a just wrapper function of
->update_pmtu(). So, it doesn't change logic
Signed-off-by: Gyeongun Kang <kyeongun15@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/gtp.c

@@ -539,7 +539,7 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct net_device *dev,
 		mtu = dst_mtu(&rt->dst);
 	}
 
-	rt->dst.ops->update_pmtu(&rt->dst, NULL, skb, mtu, false);
+	skb_dst_update_pmtu_no_confirm(skb, mtu);
 
 	if (!skb_is_gso(skb) && (iph->frag_off & htons(IP_DF)) &&
 	    mtu < ntohs(iph->tot_len)) {