Add another Rome model (#1095)

[ROCm/rccl commit: df98a6957d]

projects/rccl/tools/topo_expl/topo_expl.cpp

@@ -157,6 +157,7 @@ NodeModelDesc model_descs[] = {
   {1, "topo_8p_940vm.xml",      "single node gfx940 VM"},
   {2, "topo_8p_940vm.xml",      "2 nodes gfx940 VM"},
   {2, "topo_8p_940_16n.xml",    "2 nodes gfx940 16 NICs"},
+  {2, "topo_8p1h_6.xml",        "2 nodes 8P1H Alt."},
 };
 
 NCCL_PARAM(MaxCTAs, "MAX_CTAS", MAXCHANNELS);