camera: add power mode support

Based on commit 7036d66bec7697160ba1b2e255f1e7fae0c8c435 from CAF,
branch ics_chocolate.

Change-Id: I652d63c33db9a8da4a9f8f613be12877d032de37

Conflicts:

	camera/CameraParameters.cpp
	include/camera/CameraParameters.h