Bluetooth: Add support for adding remote OOB data for LE

This patch adds proper support for passing LE OOB data to the
hci_add_remote_oob_data() function. For LE the 192-bit values are not
valid and should therefore be passed as NULL values.

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