[IrDA]: irttp_dup spin_lock initialisation

Without this initialization one gets

kernel BUG at kernel/rtmutex_common.h:80!

This patch should also be included in the -stable kernel.

Signed-off-by: G. Liakhovetski <gl@dsa-ac.de>
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/irda/irttp.c b/net/irda/irttp.c
index a7486b3..da3f2bc 100644
--- a/net/irda/irttp.c
+++ b/net/irda/irttp.c
@@ -1455,6 +1455,7 @@
 
 	/* Not everything should be copied */
 	new->notify.instance = instance;
+	spin_lock_init(&new->lock);
 	init_timer(&new->todo_timer);
 
 	skb_queue_head_init(&new->rx_queue);