CANN: fix acl_rstd allocation size in ggml_cann_rms_norm

Fixes #15330

Adjust the allocation size of acl_rstd. The parameter `dims` is set to 3
according to the CANN documentation.

Co-authored-by: Yuchuan <yuchuan-cao@users.noreply.github.com>

Author: noemotiovon

ggml/src/ggml-cann/aclnn_ops.cpp

@@ -975,6 +975,7 @@ void ggml_cann_rms_norm(ggml_backend_cann_context& ctx, ggml_tensor* dst) {
     );
 
     // build rstd, zero...
+    int64_t acl_rstd_ne[] = {src->ne[1], src->ne[2], src->ne[3]};
     size_t acl_rstd_nb[GGML_MAX_DIMS];
     acl_rstd_nb[0] = sizeof(float);
     for (int i = 1; i < GGML_MAX_DIMS; i++) {
@@ -984,9 +985,9 @@ void ggml_cann_rms_norm(ggml_backend_cann_context& ctx, ggml_tensor* dst) {
         ctx,
         &ctx.rms_norm_zero_tensor_cache.cache,
         ctx.rms_norm_zero_tensor_cache.size,
-        src->ne,
+        acl_rstd_ne,
         acl_rstd_nb,
-        GGML_MAX_DIMS,
+        GGML_MAX_DIMS - 1,
         0.0f      // value
     );