cxgb3: Fix kernel crash caused by uninitialized l2t_entry.arpq

Commit 147e70e ("cxgb3: Use SKB list interfaces instead of home-grown
implementation.") causes a crash in t3_l2t_send_slow() when an iWARP
connection request is received.  This is because the new l2t_entry.arpq
skb queue is never initialized, and therefore trying to add an skb to
it causes a NULL dereference.  With the old code there was no need to
initialize the queues because the l2t_entry structures were zeroed,
and the code used NULL to mean empty.

Fix this by adding __skb_queue_head_init() when all the l2t_entry
structures get allocated.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/cxgb3/l2t.c

@@ -431,6 +431,7 @@ struct l2t_data *t3_init_l2t(unsigned int l2t_capacity)
 	for (i = 0; i < l2t_capacity; ++i) {
 		d->l2tab[i].idx = i;
 		d->l2tab[i].state = L2T_STATE_UNUSED;
+		__skb_queue_head_init(&d->l2tab[i].arpq);
 		spin_lock_init(&d->l2tab[i].lock);
 		atomic_set(&d->l2tab[i].refcnt, 0);
 	}