message: core(ocl): add parameter to limit device max workgroup size
  used by OpenCV
diff: @@ -1257,6 +1257,14 @@ struct Device::Impl
  else
  vendorID_ = UNKNOWN_VENDOR;
  + const size_t CV_OPENCL_DEVICE_MAX_WORK_GROUP_SIZE = utils::getConfigurationParameterSizeT("OPENCV_OPENCL_DEVICE_MAX_WORK_GROUP_SIZE", 0);
  + if (CV_OPENCL_DEVICE_MAX_WORK_GROUP_SIZE > 0)
  + {
  + const size_t new_maxWorkGroupSize = std::min(maxWorkGroupSize_, CV_OPENCL_DEVICE_MAX_WORK_GROUP_SIZE);
  + if (new_maxWorkGroupSize != maxWorkGroupSize_)
  + CV_LOG_WARNING(NULL, "OpenCL: using workgroup size: " << new_maxWorkGroupSize << " (was " << maxWorkGroupSize_ << ")");
  + maxWorkGroupSize_ = new_maxWorkGroupSize;
  + }
  #if 0
  if (isExtensionSupported("cl_khr_spir"))
  {
  