Bluetooth: Rotate outgoing ACL packets via a pending queue

To ensure that we never have more outgoing ACL buffers available than
the controller is willing to accept we should hold on to them between
calling drv->send() and getting the corresponding Number of Completed
Packets event. This patch adds a temporary FIFO in bt_dev for this.

Change-Id: I918119a03081d507de2bb4a731b2709ea99a648d
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
3 files changed