Bluetooth: Use kref for l2cap channel reference counting

This patch changes the struct l2cap_chan and associated code to use
kref api for object refcounting and freeing.

Suggested-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Jaganath Kanakkassery <jaganath.k@samsung.com>
Signed-off-by: Syam Sidhardhan <s.syam@samsung.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index d206296..7ed8e35 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -433,11 +433,10 @@
 	struct sock *sk;
 
 	struct l2cap_conn	*conn;
+	struct kref	kref;
 
 	__u8		state;
 
-	atomic_t	refcnt;
-
 	__le16		psm;
 	__u16		dcid;
 	__u16		scid;