audio effect: add flag for effects without actual processing

Add a flag for effect descriptor indicating that the effect does not
implement a process function. This tells the framework that no
latency or performance penalty comes with enabling this effect.
When this flag is set, the process function does not have to be implemented
by the effect implementation.

Bug: 31491112
Change-Id: I69e6959eb17e04266f4de3f2943c226e34868b1f
1 file changed