stagefright aacenc: Zero-initialize a struct

This avoids using uninitialized data in some cases, according
to valgrind.

Change-Id: I2eb5242b93c4d83a1cf6a15f022ec9579e0742a4
diff --git a/media/libstagefright/codecs/aacenc/src/adj_thr.c b/media/libstagefright/codecs/aacenc/src/adj_thr.c
index c656f65..7a38f0b 100644
--- a/media/libstagefright/codecs/aacenc/src/adj_thr.c
+++ b/media/libstagefright/codecs/aacenc/src/adj_thr.c
@@ -26,6 +26,7 @@
 #include "adj_thr.h"
 #include "qc_data.h"
 #include "line_pe.h"
+#include <string.h>
 
 
 #define  minSnrLimit    0x6666 /* 1 dB */
@@ -1138,6 +1139,7 @@
   Word16 maxBitresBits = elBits->maxBits;
   Word16 sideInfoBits = (qcOE->staticBitsUsed + qcOE->ancBitsUsed);
   Word16 ch;
+  memset(&peData, 0, sizeof(peData));
 
   prepareSfbPe(&peData, psyOutChannel, logSfbEnergy, sfbNRelevantLines, nChannels, AdjThrStateElement->peOffset);