Bluetooth: Do not include LE SC out-of-band data if not enabled

In case LE Secure Connections is not enabled, then the command for
returning local out-of-band data should not include the confirmation
and random value for LE SC pairing. All other fields are still valid,
but these two need to be left out. In that case it is also no needed
to generate the public/private key pair for out-of-band pairing.

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