fix npu for norm (#54204)

python/paddle/nn/layer/norm.py

@@ -986,6 +986,7 @@ class BatchNorm(Layer):
             _global_flags()['FLAGS_npu_storage_format']
             and 'npu' in get_all_custom_device_type()
         ):
+            if in_dynamic_mode():
                 with no_grad():
                     weight_trans = _C_ops.npu_identity(
                         self.weight, 3