Bluetooth: 6lowpan: Print errors during recv_pkt

This makes should make it more clear why a packet is being dropped.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 2063e96..5b91e85 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -337,6 +337,7 @@
 
 		ret = iphc_decompress(local_skb, dev, peer);
 		if (ret < 0) {
+			BT_DBG("iphc_decompress failed: %d", ret);
 			kfree_skb(local_skb);
 			goto drop;
 		}
@@ -356,6 +357,7 @@
 		consume_skb(local_skb);
 		consume_skb(skb);
 	} else {
+		BT_DBG("unknown packet type");
 		goto drop;
 	}