mac802154: turn on ACK when enabled by the upper layers

Signed-off-by: Tony Cheneau <tony.cheneau@amnesiak.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mac802154/wpan.c b/net/mac802154/wpan.c
index d20c6d3..7d3f659 100644
--- a/net/mac802154/wpan.c
+++ b/net/mac802154/wpan.c
@@ -145,6 +145,8 @@
 
 	head[pos++] = mac_cb(skb)->seq; /* DSN/BSN */
 	fc = mac_cb_type(skb);
+	if (mac_cb_is_ackreq(skb))
+		fc |= IEEE802154_FC_ACK_REQ;
 
 	if (!saddr) {
 		spin_lock_bh(&priv->mib_lock);