Camera: Add debug messages for camera latency

Log latency histogram of:
- processCaptureRequest call,
- dequeueBuffer call, and
- waiting time for handout count fall below max_buffers

Test: Camera CTS
Bug: 62651109
Change-Id: I5ee1cdb4139fa359f0887d6f6871884e28739340
(cherry picked from commit 686f644f)