Silence warning from clang

QBasicAtomicPointer is forward declared as a class, keep the actual
declaration of QBasicAtomicInteger and QBasicAtomicPointer as class with
all public members (qoldbasicatomic.h does the same).

src/corelib/thread/qbasicatomic.h:158:1: warning:
      'QBasicAtomicPointer' defined as a struct template here but
      previously declared as a class template [-Wmismatched-tags]
struct QBasicAtomicPointer
^
src/corelib/global/qglobal.h:1861:23: note: did you mean struct here?
template <typename T> class QBasicAtomicPointer;
                      ^~~~~
                      struct

Change-Id: I38c59c29d7f796dde772e7f403bbf98b04571a08
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

src/corelib/thread/qbasicatomic.h

@@ -63,8 +63,9 @@ QT_MODULE(Core)
 // New atomics
 
 template <typename T>
-struct QBasicAtomicInteger
+class QBasicAtomicInteger
 {
+public:
     typedef QAtomicOps<T> Ops;
     // static check that this is a valid integer
     typedef char PermittedIntegerType[QAtomicIntegerTraits<T>::IsInteger ? 1 : -1];
@@ -133,8 +134,9 @@ struct QBasicAtomicInteger
 typedef QBasicAtomicInteger<int> QBasicAtomicInt;
 
 template <typename X>
-struct QBasicAtomicPointer
+class QBasicAtomicPointer
 {
+public:
     typedef X *Type;
     typedef QAtomicOps<Type> Ops;
     typedef typename Ops::Type AtomicType;