net: Drop secpath on free after gro merge.

With a followup patch, a gro merged skb can have a secpath.
So drop it before freeing or reusing the skb.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/core/dev.c

@@ -4623,6 +4623,7 @@ static gro_result_t napi_skb_finish(gro_result_t ret, struct sk_buff *skb)
 	case GRO_MERGED_FREE:
 		if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) {
 			skb_dst_drop(skb);
+			secpath_reset(skb);
 			kmem_cache_free(skbuff_head_cache, skb);
 		} else {
 			__kfree_skb(skb);
@@ -4663,6 +4664,7 @@ static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
 	skb->encapsulation = 0;
 	skb_shinfo(skb)->gso_type = 0;
 	skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
+	secpath_reset(skb);
 
 	napi->skb = skb;
 }