Add missing definition for clearkey service.

android.hardware.drm@1.2-service.clearkey is not
started on boot, subsequently causing timeout error when
we run CTS test during TreeHugger presubmit test.

Test: adb shell ps -A | grep drm
  confirm service is started
Test: run CTS test
  atest CtsMediaTestCases:android.media.cts.MediaDrmMetricsTest -- --abi x86

bug: 139479420
Change-Id: I777555e74e6d18b30f396ebb751bee4c81982dfb
5 files changed