Add missing qt namespace in qthreadstorage.h

Wrap 'else QT_CONFIG(thread)' block in qthreadstorage.h with qt
namespace

Pick-to: 6.2
Fixes: QTBUG-98085
Change-Id: Ica1817fa6beeaf9e4883edaa8738f042b29f0c5e
Reviewed-by: Kirill Burtsev <kirill.burtsev@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/thread/qthreadstorage.h

@@ -158,6 +158,8 @@ QT_END_NAMESPACE
 
 #include <type_traits>
 
+QT_BEGIN_NAMESPACE
+
 template <typename T, typename U>
 inline bool qThreadStorage_hasLocalData(const QScopedPointer<T, U> &data)
 {
@@ -227,6 +229,8 @@ public:
     }
 };
 
+QT_END_NAMESPACE
+
 #endif // QT_CONFIG(thread)
 
 #endif // QTHREADSTORAGE_H