PowerManager : Make proximity check opt-in

Change-Id: I7cf64a82530da2e655018e43683ba7a5584d54f8
(cherry picked from commit 2323852b776e1ccee5dd48f88f2f7a77d96a967a)

Conflicts:
	core/res/res/values/config.xml
	core/res/res/values/symbols.xml
	services/java/com/android/server/power/PowerManagerService.java