Bluetooth: Fix local OOB data handling for SMP

We need to store the local ra/rb value in order to verify the Check
value received from the remote. This patch adds a new 'lr' for the local
ra/rb value and makes sure it gets used when verifying the DHKey Check
PDU received from the remote.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>