display: Add setSecondaryDisplayStatus API

- Clients(SecureUI/WFD FW) will use this API to set status of the
  Secondary display
- Status can be offline/pause/resume
- Secondary display will be hdmi/wfd, HWC will free up pipes for
  these displays

Change-Id: I25d5e070b60c38daeb102349bed14bb6de0a5684
8 files changed