removed redundant kGroupIndexWarpSize assign

Author: shbiswas834

fbgemm_gpu/src/sparse_ops/sparse_group_index.cu

@@ -13,12 +13,7 @@ using Tensor = at::Tensor;
 namespace fbgemm_gpu {
 namespace {
 
-#ifdef USE_ROCM
-constexpr int kGroupIndexWarpSize = kWarpSize;
-#else
 constexpr int kGroupIndexWarpSize = kWarpSize;
-#endif
-
 constexpr int GROUP_INDEX_SELECT_UNROLL_FACTOR = 1;
 constexpr int GROUP_INDEX_SELECT_COLS_PER_WARP =
     GROUP_INDEX_SELECT_UNROLL_FACTOR * kGroupIndexWarpSize;