platform: Remove mapping of android.permission.CAMERA to camera group

This mapping introduces security risk where any app with android.
permission.CAMERA can open camera driver directly without going
through mediaserver.

CRs-Fixed: 448868
Change-Id: Ic16880cfac0bc85a3e753ccd3261bfc455b02d1a
SystemUI: Fix missing context var

Change-Id: I083f85fdfec2bde88e6d8e0366d94e86eaea20cd
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>