This paves the way for eventually performing advertising changes
through the hdev->req_workqueue. Some new APIs need to be exposed from
mgmt.c to hci_request.c and vice-versa, but many of them will go away
once hdev->req_workqueue gets used.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>