net: core: Free packet properly if TTL/hop limit is 0

We drop the packet if TTL or hop limit is 0, but we should
also unref the packet in this case because we return 0 to
the caller which is not then able to free the packet because
it thinks that the packet was sent properly.

Signed-off-by: Jukka Rissanen <[email protected]>
(cherry picked from commit 2f1a134)

Author: jukkar

subsys/net/ip/net_core.c

@@ -392,6 +392,7 @@ int net_send_data(struct net_pkt *pkt)
 		 * we just silently drop the packet by returning 0.
 		 */
 		if (status == -ENOMSG) {
+			net_pkt_unref(pkt);
 			ret = 0;
 			goto err;
 		}