base

camera2:  Update camera metadata with legacy mode enum.

Bug: 15116722

- Adds enum for a device running in compatibility mode.  When running
  in compatibility mode, the Camera2 API is emulated using the
  deprecated Camera API, and many capabilities will not be supported.

Change-Id: I94f31775699447a82d53b7f2a6f9fbdc0a5afb3f