Merge pull request #26590 from Kumataro:fix26589

Support C++20 standard #26590

Close https://github.com/opencv/opencv/issues/26589
Related https://github.com/opencv/opencv_contrib/pull/3842
Related: https://github.com/opencv/opencv/issues/20269

- do not arithmetic enums and ( different enums or floating numeric) 
- remove unused variable

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/imgproc/src/histogram.cpp

@@ -1283,7 +1283,7 @@ void cv::calcHist( InputArrayOfArrays images, const std::vector<int>& channels,
     CV_OCL_RUN(images.total() == 1 && channels.size() == 1 && images.channels(0) == 1 &&
                channels[0] == 0 && images.isUMatVector() && mask.empty() && !accumulate &&
                histSize.size() == 1 && histSize[0] == BINS && ranges.size() == 2 &&
-               ranges[0] == 0 && ranges[1] == BINS,
+               ranges[0] == 0 && ranges[1] == static_cast<float>(BINS),
                ocl_calcHist(images, hist))
 
     int i, dims = (int)histSize.size(), rsz = (int)ranges.size(), csz = (int)channels.size();