Pull Request Readiness Checklist

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

• I agree to contribute to the project under Apache 2 License.
• 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
• The PR is proposed to the proper branch
• N/A There is a reference to the original bug report and related work
• N/A There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• N/A The feature is well documented and sample code can be built with the project CMake
  fix the return-type compile error in ipp_warpAffine

When building OpenCV on Windows with MSVC, if we set cmake option WITH_IPP ON and BUILD_IPP_IW OFF, then we have macro HAVE_IPP / HAVE_IPP_ICV but no HAVE_IPP_IW / HAVE_IPP_IW_LL in cvconfig.h, thus the function ipp_warpAffine will have an empty body (no return), but its signature returns bool.

Just add return false and apply CV_UNUSED to all its arguments, like what other ipp_* functions do.

The compile error on my PC is:

F:\Library\opencv\modules\imgproc\src\imgwarp.cpp(2622,118): warning C4100: 'flags': unreferenced formal parameter
F:\Library\opencv\modules\imgproc\src\imgwarp.cpp(2622,110): warning C4100: '_M': unreferenced formal parameter
F:\Library\opencv\modules\imgproc\src\imgwarp.cpp(2622,87): warning C4100: 'borderType': unreferenced formal parameter
F:\Library\opencv\modules\imgproc\src\imgwarp.cpp(2622,68): warning C4100: 'interpolation': unreferenced formal parameter
F:\Library\opencv\modules\imgproc\src\imgwarp.cpp(2622,58): warning C4100: '_dst': unreferenced formal parameter
F:\Library\opencv\modules\imgproc\src\imgwarp.cpp(2622,40): warning C4100: '_src': unreferenced formal parameter
F:\Library\opencv\modules\imgproc\src\imgwarp.cpp(2683): error C4716: 'cv::ipp_warpAffine': must return a value