Fix dismatch of std::max's arguments type on windows. (#22507)

test=develop

paddle/fluid/operators/math/sequence_pooling.cu

@@ -167,7 +167,7 @@ class SequencePoolFunctor<platform::CUDADeviceContext, T> {
     auto& lod = input.lod()[lod_level - 1];
     const size_t item_dim = output->numel() / output->dims()[0];
     dim3 threads(1024, 1);
-    dim3 grid(std::max(lod.size() - 1, 1UL), 1);
+    dim3 grid(std::max(static_cast<int>(lod.size()) - 1, 1), 1);
     if (pooltype == "MAX") {
       sequence_pool_kernel<
           T, MaxPoolFunctor<T>><<<grid, threads, 0, context.stream()>>>(
@@ -331,7 +331,7 @@ class SequencePoolGradFunctor<platform::CUDADeviceContext, T> {
     auto& lod = in_grad->lod()[lod_level - 1];
     const size_t item_dim = in_grad->numel() / in_grad->dims()[0];
     dim3 threads(1024, 1);
-    dim3 grid(std::max(lod.size() - 1, 1UL), 1);
+    dim3 grid(std::max(static_cast<int>(lod.size()) - 1, 1), 1);
     if (pooltype == "MAX") {
       sequence_pool_grad_kernel<
           T, MaxPoolGradFunctor<T>><<<grid, threads, 0, context.stream()>>>(