Bluetooth: remove lock from struct conn_hash

It isn't used anywhere.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index fb2cce2..7f815c0 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -61,7 +61,6 @@
 
 struct hci_conn_hash {
 	struct list_head list;
-	spinlock_t       lock;
 	unsigned int     acl_num;
 	unsigned int     sco_num;
 	unsigned int     le_num;