constify JNINativeMethod function pointer tables

Change-Id: I4036c924958221cbc644724f8eb01c5de3cd7954
diff --git a/core/jni/android_os_SystemClock.cpp b/core/jni/android_os_SystemClock.cpp
index dfe024e..d98407d 100644
--- a/core/jni/android_os_SystemClock.cpp
+++ b/core/jni/android_os_SystemClock.cpp
@@ -104,7 +104,7 @@
 /*
  * JNI registration.
  */
-static JNINativeMethod gMethods[] = {
+static const JNINativeMethod gMethods[] = {
     /* name, signature, funcPtr */
     { "uptimeMillis",      "()J",
             (void*) android_os_SystemClock_uptimeMillis },