PML/UCX: suppressed compilation warning

Signed-off-by: Sergey Oblomov <sergeyo@mellanox.com>

ompi/mca/pml/ucx/pml_ucx.c

@@ -447,7 +447,7 @@ int mca_pml_ucx_del_procs(struct ompi_proc_t **procs, size_t nprocs)
     mca_pml_ucx_waitall(dreqs, &num_reqs);
     free(dreqs);
 
-    opal_pmix.fence_nb(NULL, 0, mca_pml_fence_complete_cb, &fenced);
+    opal_pmix.fence_nb(NULL, 0, mca_pml_fence_complete_cb, (void*)&fenced);
     while (!fenced) {
         ucp_worker_progress(ompi_pml_ucx.ucp_worker);
     }