struct effect_descriptor_s const correctness

Also struct audio_stream in audio_stream_frame_size

Change-Id: Ie0de708e38a1850c186a8b4eb5f491adc44b3275
diff --git a/modules/audio/audio_policy.c b/modules/audio/audio_policy.c
index a44ea77..2dd3dbe 100644
--- a/modules/audio/audio_policy.c
+++ b/modules/audio/audio_policy.c
@@ -193,13 +193,13 @@
 }
 
 static audio_io_handle_t ap_get_output_for_effect(struct audio_policy *pol,
-                                            struct effect_descriptor_s *desc)
+                                            const struct effect_descriptor_s *desc)
 {
     return 0;
 }
 
 static int ap_register_effect(struct audio_policy *pol,
-                              struct effect_descriptor_s *desc,
+                              const struct effect_descriptor_s *desc,
                               audio_io_handle_t output,
                               uint32_t strategy,
                               int session,