constify JNINativeMethod function pointer tables

Change-Id: I4036c924958221cbc644724f8eb01c5de3cd7954
diff --git a/core/jni/android_media_ToneGenerator.cpp b/core/jni/android_media_ToneGenerator.cpp
index 243f040..aec6263 100644
--- a/core/jni/android_media_ToneGenerator.cpp
+++ b/core/jni/android_media_ToneGenerator.cpp
@@ -123,7 +123,7 @@
 
 // ----------------------------------------------------------------------------
 
-static JNINativeMethod gMethods[] = {
+static const JNINativeMethod gMethods[] = {
     { "startTone", "(II)Z", (void *)android_media_ToneGenerator_startTone },
     { "stopTone", "()V", (void *)android_media_ToneGenerator_stopTone },
     { "getAudioSessionId", "()I", (void *)android_media_ToneGenerator_getAudioSessionId},