bluetooth: handle l2cap_create_connless_pdu() errors

l2cap_create_connless_pdu() can sometimes return ERR_PTR(-ENOMEM) or
ERR_PTR(-EFAULT).

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: David S. Miller <davem@davemloft.net>