hwc2: get display configs and attributes

Allow the client to query display configs and attributes

Test: Add "TARGET_USES_HWC2 := true" to BoardConfig.mk.
      Recompile.
      Run testcases: https://android-review.googlesource.com/#/q/project:
            platform/frameworks/native+branch:master+topic:test-hwc2

Change-Id: I302c7ca4bdcc34bbed464083c7a9622eb836b401
5 files changed