netfilter: flowtable: Fix setting forgotten NF_FLOW_HW_DEAD flag

During the refactor this was accidently removed.

Fixes: ae290450 ("netfilter: flowtable: add nf_flow_offload_tuple() helper")
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_flow_table_offload.c

@@ -675,6 +675,7 @@ static void flow_offload_work_del(struct flow_offload_work *offload)
 {
 	flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_ORIGINAL);
 	flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_REPLY);
+	set_bit(NF_FLOW_HW_DEAD, &offload->flow->flags);
 }
 
 static void flow_offload_tuple_stats(struct flow_offload_work *offload,