Reference nativehelper/jni.h as jni.h

nativehelper will no longer export nativehelper/jni.h so that everywhere
can reference this file with the same name.

Bug: 63762847
Change-Id: I58374051efa51ba02e6e4688462bf7e7a484d798
diff --git a/pico/compat/jni/com_android_tts_compat_SynthProxy.cpp b/pico/compat/jni/com_android_tts_compat_SynthProxy.cpp
index 83633db..fd958f9 100644
--- a/pico/compat/jni/com_android_tts_compat_SynthProxy.cpp
+++ b/pico/compat/jni/com_android_tts_compat_SynthProxy.cpp
@@ -20,7 +20,7 @@
 #define LOG_TAG "SynthProxyJNI"
 
 #include <utils/Log.h>
-#include <nativehelper/jni.h>
+#include <jni.h>
 #include <nativehelper/JNIHelp.h>
 #include <android_runtime/AndroidRuntime.h>
 #include <android_runtime/Log.h>