message: imgproc(color): clarify error message
diff: @@ -224,7 +224,10 @@ struct OclHelper
  int scn = src.channels();
  int depth = src.depth();
  - CV_Assert( VScn::contains(scn) && VDcn::contains(dcn) && VDepth::contains(depth) );
  + CV_Check(scn, VScn::contains(scn), "Invalid number of channels in input image");
  + CV_Check(dcn, VDcn::contains(dcn), "Invalid number of channels in output image");
  + CV_CheckDepth(depth, VDepth::contains(depth), "Unsupported depth of input image");
  +
  switch (sizePolicy)
  {
  case TO_YUV:
  