Bluetooth: hci_core: Fix UAF in hci_unregister_dev()

hci_unregister_dev() does not disable cmd_timer and ncmd_timer
before the hci_dev structure is freed. If a timeout fires
during device teardown, the callback dereferences freed memory
(including the hdev->reset function pointer), leading to a
use-after-free.

Add disable_delayed_work_sync() calls alongside the existing
disable_work_sync() calls to ensure both timers are fully
quiesced before teardown proceeds.

Fixes: 0d151a1037 ("Bluetooth: hci_core: cancel all works upon hci_unregister_dev()")
Signed-off-by: Jordan Walters <jaggyaur@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

net/bluetooth/hci_core.c

@@ -2671,6 +2671,8 @@ void hci_unregister_dev(struct hci_dev *hdev)
 	disable_work_sync(&hdev->tx_work);
 	disable_work_sync(&hdev->power_on);
 	disable_work_sync(&hdev->error_reset);
+	disable_delayed_work_sync(&hdev->cmd_timer);
+	disable_delayed_work_sync(&hdev->ncmd_timer);
 
 	hci_cmd_sync_clear(hdev);