Fix bug when eigen_device() is nullptr in top_k (#40459)

paddle/phi/kernels/gpu/top_k_kernel.cu

@@ -78,8 +78,9 @@ void TopkKernel(const Context& dev_ctx,
     // The conclusion is drawn from the data through multiple sets of
     // statistics
     if (input_width >= 128 && k >= input_width * 0.75) {
-      if (ops::SortTopk<T>(
-              paddle::platform::CUDADeviceContext(dev_ctx.GetPlace()),
+      auto* ctx = reinterpret_cast<const paddle::platform::CUDADeviceContext*>(
+          &dev_ctx);
+      if (ops::SortTopk<T>(*ctx,
                            input,
                            input_width,
                            input_height,
@@ -181,8 +182,9 @@ void TopkKernel(const Context& dev_ctx,
     // The conclusion is drawn from the data through multiple sets of
     // statistics
     if (input_width >= 128 && k >= input_width * 0.75) {
-      if (ops::SortTopk<T>(
-              paddle::platform::CUDADeviceContext(dev_ctx.GetPlace()),
+      auto* ctx = reinterpret_cast<const paddle::platform::CUDADeviceContext*>(
+          &dev_ctx);
+      if (ops::SortTopk<T>(*ctx,
                            &trans_input,
                            input_width,
                            input_height,