mac802154: monitor device support

Support for monitor device intended to capture all the network activity.
This interface could be used by networks sniffers and is already
supported by WireShark. That's a good test point to check that basic
MAC support works.

Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
index d15738f..4a7d76d 100644
--- a/net/mac802154/rx.c
+++ b/net/mac802154/rx.c
@@ -76,6 +76,7 @@
 		skb_trim(skb, skb->len - 2); /* CRC */
 	}
 
+	mac802154_monitors_rx(priv, skb);
 out:
 	dev_kfree_skb(skb);
 	return;