dpctl: Skip invoking qsort on empty list
Clang reports "Argument with 'nonnull' attribute passed null" warning.
@@ -555,7 +555,9 @@ show_dpif(struct dpif *dpif, struct dpctl_params *dpctl_p)
n_port_nos++;
}
+ if (port_nos) {
qsort(port_nos, n_port_nos, sizeof *port_nos, compare_port_nos);
+ }
for (int i = 0; i < n_port_nos; i++) {
if (dpif_port_query_by_number(dpif, port_nos[i], &dpif_port)) {
