Bluetooth: Add refcnt to struct l2cap_chan

struct l2cap_chan has now its own refcnt that is compatible with the
socket refcnt, i.e., we won't see sk_refcnt = 0 and chan->refcnt > 0.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

include/net/bluetooth/l2cap.h

@@ -289,6 +289,8 @@ struct l2cap_chan {
 
 	__u8		state;
 
+	atomic_t	refcnt;
+
 	__le16		psm;
 	__u16		dcid;
 	__u16		scid;