Bluetooth: Pass full hci_dev struct to mgmt callbacks

The current global pending command list in mgmt.c is racy. Possibly the
simplest way to fix it is to have per-hci dev lists instead of a global
one (all commands that need a pending struct are hci_dev specific).
This way the list can be protected using the already existing per-hci
dev lock. To enable this refactoring the first thing that needs to be
done is to ensure that the mgmt functions have access to the hci_dev
struct (instead of just the dev id).

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>