SurfaceTexture.cpp: use proper nativehelper headers

libnativehelper exports headers under nativehelper. These were
available before incorrectly as global headers in order to give
access to jni.h.

Test: SurfaceTexture.cpp finds headers
Bug: 63762847
Change-Id: I3ec1b888c226c2894649d9f9a8f8203891c1ab02
(cherry picked from commit 849252c469396a759c394dc6382470a6a07d6587)
diff --git a/core/jni/android/graphics/SurfaceTexture.cpp b/core/jni/android/graphics/SurfaceTexture.cpp
index 9242b70..d098a35 100644
--- a/core/jni/android/graphics/SurfaceTexture.cpp
+++ b/core/jni/android/graphics/SurfaceTexture.cpp
@@ -34,8 +34,8 @@
 #include <utils/misc.h>
 
 #include "jni.h"
-#include "JNIHelp.h"
-#include "ScopedLocalRef.h"
+#include <nativehelper/JNIHelp.h>
+#include <nativehelper/ScopedLocalRef.h>
 
 // ----------------------------------------------------------------------------