Remove MSCCL switch case fall-through by adding break statement. (#1342)

src/misc/msccl/msccl_lifecycle.cc

@@ -595,6 +595,7 @@ ncclResult_t mscclEnqueueCheck(
         }
       threadLocalStatus.groupStatus = mscclGroupUnsupportedOp;
       NCCLCHECK(mscclFallBackSavedParams());
+      break;
     case mscclGroupUnsupportedOp:
       NCCLCHECK(mscclFallBackSavedParams());
       break;