Bluetooth: hci_core: Fix leaking sent_cmd skb

sent_cmd memory is not freed before freeing hci_dev causing it to leak
it contents.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_core.c

@@ -2738,6 +2738,7 @@ void hci_release_dev(struct hci_dev *hdev)
 	hci_dev_unlock(hdev);
 
 	ida_simple_remove(&hci_index_ida, hdev->id);
+	kfree_skb(hdev->sent_cmd);
 	kfree(hdev);
 }
 EXPORT_SYMBOL(hci_release_dev);