test: net: ipv6_fragment: Set link layer protocol type for a packet

The test_send_ipv6_fragment_without_hbho() test did not set link layer
protocol type for the packet. It is needed in this case because we
are sending a ready made packet and the protocol type is unknown
otherwise.

Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>

Author: jukkar

tests/net/ipv6_fragment/src/main.c

@@ -2090,6 +2090,7 @@ ZTEST(net_ipv6_fragment, test_send_ipv6_fragment_without_hbho)
 					AF_UNSPEC, 0, ALLOC_TIMEOUT);
 	zassert_not_null(pkt, "packet");
 
+	net_pkt_set_ll_proto_type(pkt, NET_ETH_PTYPE_IPV6);
 	net_pkt_set_family(pkt, AF_INET6);
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv6_hdr));
 	net_pkt_set_ipv6_ext_len(pkt, NET_IPV6_FRAGH_LEN); /* without hbho*/