[NANO130] Refine sleep code
[NANO130] Refine sleep code

1. Remove stale code with mbed OS 3.
2. Remove check for busy peripherals unorganizedly. This would be supported by e.g. official sleep manager.

Archcady/mbed-os,infinnovation/mbed-os,ryankurte/mbed-os,kjbracey-arm/mbed,mazimkhan/mbed-os,mazimkhan/mbed-os,c1728p9/mbed-os,kjbracey-arm/mbed,c1728p9/mbed-os,karsev/mbed-os,HeadsUpDisplayInc/mbed,ryankurte/mbed-os,Archcady/mbed-os,infinnovation/mbed-os,betzw/mbed-os,infinnovation/mbed-os,karsev/mbed-os,andcor02/mbed-os,betzw/mbed-os,mazimkhan/mbed-os,HeadsUpDisplayInc/mbed,andcor02/mbed-os,mbedmicro/mbed,infinnovation/mbed-os,infinnovation/mbed-os,c1728p9/mbed-os,karsev/mbed-os,Archcady/mbed-os,HeadsUpDisplayInc/mbed,karsev/mbed-os,mazimkhan/mbed-os,Archcady/mbed-os,betzw/mbed-os,c1728p9/mbed-os,CalSol/mbed,mazimkhan/mbed-os,HeadsUpDisplayInc/mbed,c1728p9/mbed-os,andcor02/mbed-os,ryankurte/mbed-os,CalSol/mbed,andcor02/mbed-os,HeadsUpDisplayInc/mbed,karsev/mbed-os,kjbracey-arm/mbed,infinnovation/mbed-os,c1728p9/mbed-os,betzw/mbed-os,ryankurte/mbed-os,karsev/mbed-os,HeadsUpDisplayInc/mbed,mazimkhan/mbed-os,andcor02/mbed-os,Archcady/mbed-os,ryankurte/mbed-os,mbedmicro/mbed,mbedmicro/mbed,CalSol/mbed,betzw/mbed-os,Archcady/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,betzw/mbed-os,andcor02/mbed-os,CalSol/mbed,mbedmicro/mbed,ryankurte/mbed-os,CalSol/mbed,CalSol/mbed