Merge pull request #23929 from CNClareChen:4.x

* Optimize some function with lasx.

Optimize some function with lasx. #23929

This patch optimizes some lasx functions and reduces the runtime of opencv_test_core from 662,238ms to 633603ms on the 3A5000 platform.

### 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
- [x] 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/core/src/system.cpp

@@ -427,6 +427,7 @@ struct HWFeatures
 
         g_hwFeatureNames[CPU_RVV] = "RVV";
 
+        g_hwFeatureNames[CPU_LSX]  = "LSX";
         g_hwFeatureNames[CPU_LASX] = "LASX";
     }
 
@@ -703,6 +704,10 @@ struct HWFeatures
         have[CV_CPU_RVV] = true;
     #endif
 
+    #if defined __loongarch_sx
+        have[CV_CPU_LSX] = true;
+    #endif
+
     #if defined __loongarch_asx
         have[CV_CPU_LASX] = true;
     #endif