audio HAL: release audio pre processing buffers.

Buffers allocated for audio pre processing are not released
when an input stream is closed.

Issue 5753047.

Change-Id: Ie8fd5f49d97e9bebc70fc38de0844a79074ac526

audio/audio_hw.c

@@ -2457,6 +2457,10 @@ static void adev_close_input_stream(struct audio_hw_device *dev,
         free(in->buffer);
         release_resampler(in->resampler);
     }
+    if (in->proc_buf)
+        free(in->proc_buf);
+    if (in->ref_buf)
+        free(in->ref_buf);
 
     free(stream);
     return;