Bluetooth: Use explicit header and body length for L2CAP SKB allocation

When allocating the L2CAP SKB for transmission, provide the upper layers
with a clear distinction on what is the header and what is the body
portion of the SKB.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 18f4f27..9251103 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -600,6 +600,7 @@
 	void			(*set_shutdown) (struct l2cap_chan *chan);
 	long			(*get_sndtimeo) (struct l2cap_chan *chan);
 	struct sk_buff		*(*alloc_skb) (struct l2cap_chan *chan,
+					       unsigned long hdr_len,
 					       unsigned long len, int nb);
 };