Increment reference count when restoring reference

Otherwise the count will be wrong after an out of memory failure in
reinterpretAsFormat.

Pick-to: 6.2 5.15
Fixes: QTBUG-98377
Change-Id: Ice51d47a6db9277126a5c7337e14aaf5ddee3a10
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

src/gui/image/qimage.cpp

@@ -2332,6 +2332,7 @@ bool QImage::reinterpretAsFormat(Format format)
         // In case detach() ran out of memory
         if (!d) {
             d = oldD;
+            d->ref.ref();
             return false;
         }
     }