sdm: Add support for HDR

- Add LayerRequests to SDM Layer Interface, which will
  be used in informing any requests from SDM to client.
- Check for color metadata from client and handle
  HDR content.
- Include GPU Tonemapper to tonemap any requests
  coming from SDM

Change-Id: Idd1882ffab77fc3bff296114f36fb30bff4a4530
Crs-fixed: 1092142
15 files changed