frameworks/base: 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: modules using frameworks/base find headers
Bug: 63762847
Change-Id: I0f9f231acdebe460f279135462f43d3e32eff64d
diff --git a/core/jni/android_os_HwParcel.cpp b/core/jni/android_os_HwParcel.cpp
index 6ea809a..b412b6a 100644
--- a/core/jni/android_os_HwParcel.cpp
+++ b/core/jni/android_os_HwParcel.cpp
@@ -24,7 +24,7 @@
 #include "android_os_HwBlob.h"
 #include "android_os_HwRemoteBinder.h"
 
-#include <JNIHelp.h>
+#include <nativehelper/JNIHelp.h>
 #include <android_runtime/AndroidRuntime.h>
 #include <hidl/HidlTransportSupport.h>
 #include <hidl/Status.h>