Audio: Volume: No update of process function for every ramp value

The volume process function for pass-through can be changed
when all ramps are completed. This change that avoids processing
function lookup in worst case every 128 us is measured to
save in TGL platform about 1 MCPS from CPU_PEAK(MAX).

Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

src/audio/volume/volume.c

@@ -347,7 +347,8 @@ static inline void volume_ramp(struct processing_module *mod)
 		}
 	}
 
-	set_volume_process(cd, dev, true);
+	if (cd->is_passthrough)
+		set_volume_process(cd, dev, true);
 }
 
 /**