Bluetooth: Compile only required parts of keys support

Depending on BR/EDR and SMP support only subset of keys functionality
is needed. This fix compilation if SMP is disabled and BR/EDR is
enabled.

Change-Id: Icf4b5ad1a214e514e03c4c9a359d151e69cab2ab
Signed-off-by: Szymon Janc <ext.szymon.janc@tieto.com>