Bluetooth: Use privacy mode for non-connectable advertising

When enabling non-connectable advertising, there is no need to advertise
with a public address or static address. In case LE privacy has not been
enabled a unresolvable private address will be used.

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