Bug 1360321 - 2. Fix cast warning on AArch64 in plugin code; r=snorp

Fix a warning on AArch64 for casting to pointer.

MozReview-Commit-ID: 6zjYdN8ta9d

dom/plugins/base/android/ANPSurface.cpp

@@ -110,7 +110,7 @@ static inline void* getSurface(JNIEnv* env, jobject view) {
   env->DeleteLocalRef(holder);
   env->DeleteLocalRef(surface);
 
-  return (void*)surfacePointer;
+  return reinterpret_cast<void*>(uintptr_t(surfacePointer));
 }
 
 static ANPBitmapFormat convertPixelFormat(int32_t format) {