Use audio_session_t consistently

Bug: 27562099
Change-Id: I328d8226191386b163f2ace41233607294c50dcd
diff --git a/media/libmedia/Visualizer.cpp b/media/libmedia/Visualizer.cpp
index f5c1b1f..31e310b 100644
--- a/media/libmedia/Visualizer.cpp
+++ b/media/libmedia/Visualizer.cpp
@@ -38,7 +38,7 @@
          int32_t priority,
          effect_callback_t cbf,
          void* user,
-         int sessionId)
+         audio_session_t sessionId)
     :   AudioEffect(SL_IID_VISUALIZATION, opPackageName, NULL, priority, cbf, user, sessionId),
         mCaptureRate(CAPTURE_RATE_DEF),
         mCaptureSize(CAPTURE_SIZE_DEF),