Correct function that wasn't returning a value (#2045)

Found when using a newer version of gcc

Authors:
  - Robert Maynard (https://github.com/robertmaynard)

Approvers:
  - Ben Frederickson (https://github.com/benfred)

URL: #2045

cpp/include/raft/random/device/sample.cuh

@@ -35,7 +35,7 @@ namespace raft::random::device {
  * @return only the thread0 will contain valid reduced result
  */
 template <typename T, typename rng_t, typename i_t = int>
-DI T warp_random_sample(rng_t& rng, T& weight, i_t& idx)
+DI void warp_random_sample(rng_t& rng, T& weight, i_t& idx)
 {
   // Todo(#1491): benchmark whether a scan and then selecting within the ranges is more efficient.
   static_assert(std::is_integral<T>::value, "The type T must be an integral type.");
@@ -101,4 +101,4 @@ DI i_t block_random_sample(rng_t rng, T* shbuf, T weight = 1, i_t idx = threadId
   return idx;
 }
 
-}  // namespace raft::random::device
+}  // namespace raft::random::device