Move services/powermanager from frameworks/base to frameworks/native

Move services/powermanager into frameworks/native so audioflinger can
use it.  Note that this is not the same as a PowerManagerService,
which is part of systemserver and handles turning the screen on and
off, etc.  This is just a binder interface to allow taking wakelocks.

Change-Id: I6b6a8b41cdbad17e826fda45aab5f059f22fc64e