Merge pull request #27976 from asmorkalov:as/size_t_fix_win32

Fixed ptrdiff_t cast on windows 32-bit #27976

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- [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
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

modules/imgcodecs/src/utils.cpp

@@ -51,13 +51,6 @@ int validateToInt(size_t sz)
     return valueInt;
 }
 
-int64_t validateToInt64(ptrdiff_t sz)
-{
-    int64_t valueInt = static_cast<int64_t>(sz);
-    CV_Assert((ptrdiff_t)valueInt == sz);
-    return valueInt;
-}
-
 #define  SCALE  14
 #define  cR  (int)(0.299*(1 << SCALE) + 0.5)
 #define  cG  (int)(0.587*(1 << SCALE) + 0.5)