Merge pull request #25024 from vrabaud:neon

Replace legacy __ARM_NEON__ by __ARM_NEON #25024

Even ACLE 1.1 referes to __ARM_NEON
https://developer.arm.com/documentation/ihi0053/b/?lang=en

### 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
- [ ] 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

cmake/checks/cpu_neon.cpp

@@ -5,7 +5,7 @@
 # include <Intrin.h>
 # include <arm_neon.h>
 # define CV_NEON 1
-#elif defined(__ARM_NEON__) || (defined (__ARM_NEON) && defined(__aarch64__))
+#elif defined(__ARM_NEON)
 #  include <arm_neon.h>
 #  define CV_NEON 1
 #endif