Update TODO docs in TunerClient on resource id/handle mapping

The resource id/handle mapping is no longer needed in the TunerClient
once the TunerService migration is done.

The mapping should only be maintained in the TunerService

Test: make
Bug: 186785141
Change-Id: Idfb02fe5935d9b25aac749c0f77eda111e0959ea
1 file changed