More compass calibration changes

 * Do calibration on boot completed, so we can retain compass
   as owner of sysfs nodes.

Change-Id: I6789e6e77f0ee601b13f325b52086c8809981fbe
Change group and permissions for flash led

 * Change group to camera, so we avoid having the node as world writable

Change-Id: I886039e8f94ba53be4d2fe7be7cc9a648b3d406c