Bluetooth: Add L2CAP create channel request handling

The L2CAP create channel request is very similar to an L2CAP connect
request, but it has an additional parameter for the controller ID.  If
the controller id is 0, the channel is set up on the BR/EDR controller
(just like a connect request).  Using a valid high speed controller ID
will cause the channel to be initially created on that high speed
controller.  While the L2CAP data will be initially routed over the
AMP controller, the L2CAP fixed signaling channel only uses BR/EDR.

When a create channel request is received for a high speed controller,
a pending response is always sent first.  After the high speed
physical and logical links are complete a success response will be
sent.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>