This patch implements cv_hal_LU/cv_hal_Cholesky/cv_hal_SVD/cv_hal_QR function in RVV_HAL using native intrinsics, optimizing the performance for cv::solve with method DECOMP_LU/DECOMP_SVD/DECOMP_CHOLESKY/DECOMP_QR and data types 32FC1/64FC1.

Tested on MUSE-PI (Spacemit X60) for both gcc 14.2 and clang 20.0.

$ ./opencv_test_core --gtest_filter="*Solve*:*SVD*:*Cholesky*"
$ ./opencv_perf_core --gtest_filter="*SolveTest*" --perf_min_samples=100 --perf_force_samples=100

The tail of the perf table is shown below since the table is too long.

View the full perf table here: hal_rvv_solve.pdf

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
• 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