Fix unused variable warning in Sorting.cu (pytorch#71555)

Summary: Pull Request resolved: pytorch#71555

Test Plan: Sandcastle

Reviewed By: malfet, mruberry

Differential Revision: D33675174

fbshipit-source-id: c849b809d17d8c51b4ddba24ec5e2ae7bd1fa69a
(cherry picked from commit 440fca6)

aten/src/ATen/native/cuda/Sorting.cu

@@ -182,6 +182,7 @@ struct KthValueLauncher {
       int collapse_self_dim,
       int64_t num_slices,
       int64_t slice_size) {
+    (void)collapse_indices_dim; // Suppress unused variable warning
     dim3 grid;
     if (!getGridFromTiles(num_slices, grid)) {
       AT_ERROR("slices are too many");
@@ -219,6 +220,7 @@ struct MedianLauncher {
       int collapse_self_dim,
       int64_t num_slices,
       int64_t slice_size) {
+    (void)collapse_values_dim; // Suppress unused variable warning
     (void)collapse_indices_dim; // Suppress unused variable warning
     dim3 grid;
     if (!getGridFromTiles(num_slices, grid)) {