Do not log error if HAL does not support VOIP volume.

Some HAL implementations return INVALID_OPERATION when set_volume isn't supported. Currently, this log would get printed every iteration of the audio loop. Since AudioFlinger will fallback to software-based volume control, to prevent log spam, don't log this error.


Test: Manual, logging removed.
Change-Id: I5d06fadbcbec105fbec6289f8c03db1451cc46be