power: Use a constructor for initialization.

Perform initialization (or cleanup) in a special
constructor (or destructor) function that gets
invoked when the power HAL library is loaded
(or unloaded). Remove code that is made redundant
by doing this. Also remove other parts of the code
which are no longer used.

Change-Id: I6a08c998c32fb57d0c7975bc814f7d87cd1104d1
2 files changed