Fix initialization of AAC presentation struct

Otherwise the new size checks trip on this.

Bug: 27207275
Change-Id: I1f8f01097e3a88ff041b69279a6121be842f1766
(cherry picked from commit 3e5d6d1b67a542d6e066b1e67857ca20dd7872b7)
diff --git a/media/libstagefright/ACodec.cpp b/media/libstagefright/ACodec.cpp
index 8d9bd21..6399b79 100644
--- a/media/libstagefright/ACodec.cpp
+++ b/media/libstagefright/ACodec.cpp
@@ -2418,6 +2418,7 @@
             : OMX_AUDIO_AACStreamFormatMP4FF;
 
     OMX_AUDIO_PARAM_ANDROID_AACPRESENTATIONTYPE presentation;
+    InitOMXParams(&presentation);
     presentation.nMaxOutputChannels = maxOutputChannelCount;
     presentation.nDrcCut = drc.drcCut;
     presentation.nDrcBoost = drc.drcBoost;