Bluetooth: controller: Remove public address config option

Since this presents a risk of public Bluetooth address duplication in
the wild by compiling once with a particular address and then flashing
the same image to multiple devices, a decision has been taken to remove
that config option and replace it later with another mechanism.

Change-Id: I068db25b2996c2409630554b1819b6adc48226cd
Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>