Make sure to check the tty-device pointer before looking up the sibling
platform device to avoid dereferencing a NULL-pointer when the tty is
one end of a Unix98 pty.
Fixes: 0395ffc1ee05 ("Bluetooth: hci_bcm: Add PM for BCM devices")
Cc: stable <stable@vger.kernel.org>     # 4.3
Cc: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
 
        hu->priv = bcm;
 
+       if (!hu->tty->dev)
+               goto out;
+
        mutex_lock(&bcm_device_lock);
        list_for_each(p, &bcm_device_list) {
                struct bcm_device *dev = list_entry(p, struct bcm_device, list);
        }
 
        mutex_unlock(&bcm_device_lock);
-
+out:
        return 0;
 }