Resolve deadlock between ActivityManagerService and PowerManagerService

ActivityManagerService lock and PowerManagerService.mLock can
be acquired in different threads in different orders.
registerReceiver() here tries to acquire ActivityManagerService
internally while holding mLock. A particular call from
WindowManagerService acquires these locks in reverse order.
This deadlock can be resolved by moving registerReceiver()
to another thread.

https://code.google.com/p/android/issues/detail?id=215254



Change-Id: I12cd610e61f212a3fb5e441f2c7a557c90afbda4
Signed-off-by: Shibin George <shibing@codeaurora.org>