Bluetooth: Always call smp_distribute_keys() from a workqueue

Bluetooth: Always call smp_distribute_keys() from a workqueue

The smp_distribute_keys() function calls smp_notify_keys() which in turn
calls l2cap_conn_update_id_addr(). The l2cap_conn_update_id_addr()
function will iterate through all L2CAP channels for the respective
connection: lock the channel, update the address information and unlock
the channel.

Since SMP is now using l2cap_chan callbacks each callback is called with
the channel lock held. Therefore, calling l2cap_conn_update_id_addr()
would cause a deadlock calling l2cap_chan_lock() on the SMP channel.
This patch moves calling smp_distribute_keys() through a workqueue so
that it is never called from an L2CAP channel callback.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>