Add back missing net flush (#1376)

src/graph/paths.cc

@@ -458,6 +458,7 @@ ncclResult_t ncclTopoNeedFlush(struct ncclTopoSystem* system, int64_t busId, int
   NCCLCHECK(ncclTopoIdToIndex(system, GPU, busId, &g));
   struct ncclTopoNode* gpu = system->nodes[GPU].nodes+g;
 #if defined(__HIP_PLATFORM_AMD__) || defined(__HIPCC__)
+  *flush = 1;
 #else
   // Flush is required on Ampere and earlier
   *flush = gpu->gpu.cudaCompCap < 90 ? 1 : ncclParamNetForceFlush();