codec2: a workaround to solve backward compatibility issue

As framework change depends on HAL change . In those platforms only
have framework change, the empty work couldn't be handled properly.
Then the result C2_NOT_FOUND will be returned and framework will report
a fatal error to client. We have to avoid such dependency issue

CRs-Fixed: 2916108

Change-Id: I5270f5e2bd1922b84fb34364bb4cb8522ff389ec