SnapdragonCamera: hide the preview surface during suspend

Occasionally, the previous preview frame is presented and
caused the screen flashing, when continuously triggering
suspend/resume.
To resolve the issue, hide the preview surface during
suspend and make it visible during resume. This helps
to clear the remaining preview frames in the buffer.

CRs-Fixed: 991416
Change-Id: I96fff0fdae6bd14263f33b1a9032604596cf49c1
2 files changed