Merge pull request #27795 from amd:fast_gaussian_simd

Improved Gaussian Blur #27795

- Horizontal and vertical kernels of 3N131 and 5N14641 are combined for non-border(inner) regions.
- Temporary storage of intermediate results are avoided by combining the kernels.
- Further refinement of other 3N, 5N to be added later.

### 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
- [ ] 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/CMakeLists.txt

@@ -8,7 +8,7 @@ ocv_add_dispatched_file(color_rgb SSE2 SSE4_1 AVX2)
 ocv_add_dispatched_file(color_yuv SSE2 SSE4_1 AVX2)
 ocv_add_dispatched_file(median_blur SSE2 SSE4_1 AVX2 AVX512_SKX)
 ocv_add_dispatched_file(morph SSE2 SSE4_1 AVX2)
-ocv_add_dispatched_file(smooth SSE2 SSE4_1 AVX2)
+ocv_add_dispatched_file(smooth SSE2 SSE4_1 AVX2 AVX512_ICL)
 ocv_add_dispatched_file(sumpixels SSE2 AVX2 AVX512_SKX)
 ocv_define_module(imgproc opencv_core WRAP java objc python js)