winrt: Fixup for 79697d9f

Task-number: QTBUG-56340
Change-Id: I9a3876d413d0d93d9ad74332677ff0244fb2e00a
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

src/plugins/position/winrt/qgeopositioninfosource_winrt.cpp

@@ -491,8 +491,9 @@ HRESULT QGeoPositionInfoSourceWinRT::onPositionChanged(IGeolocator *locator, IPo
     if (SUCCEEDED(hr) && heading) {
         double value;
         hr = heading->get_Value(&value);
-        double mod = 360;
+        double mod = 0;
         value = modf(value, &mod);
+        value += static_cast<int>(mod) % 360;
         if (value >=0 && value <= 359) // get_Value might return nan/-nan
             currentInfo.setAttribute(QGeoPositionInfo::Direction, value);
     }