Bluetooth: controller: Avoid warning with privacy disabled
Bluetooth: controller: Avoid warning with privacy disabled

To avoid warnings (seen on some machines) that a function reaches its
end without returning a value, conditionally compile the function in a
way that this cannot happen.

Signed-off-by: Carles Cufi <853081dc8dca4fe6a7e3c984752718b5db36e060@nordicsemi.no>

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