Bluetooth: Configure appropriate timeouts for AMP controllers

The L2CAP spec recommends specific retransmit and monitor timeouts for
ERTM channels that are on AMP controllers.  These timeouts are
calculated from the AMP controller's best effort flush timeout.

BR/EDR controllers use the default retransmit and monitor timeouts.

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