util: Update the inconsistent and outdated comments

The codes were updated to allow to reset the device as long as
there is no devices/functions behind the same bus. However, the
comments were kept without touched.

src/util/pci.c

@@ -605,10 +605,9 @@ pciTrySecondaryBusReset(pciDevice *dev,
     uint16_t ctl;
     int ret = -1;
 
-    /* For now, we just refuse to do a secondary bus reset
-     * if there are other devices/functions behind the bus.
-     * In future, we could allow it so long as those devices
-     * are not in use by the host or other guests.
+    /* Refuse to do a secondary bus reset if there are other
+     * devices/functions behind the bus are used by the host
+     * or other guests.
      */
     if ((conflict = pciBusContainsActiveDevices(dev, inactiveDevs))) {
         virReportError(VIR_ERR_INTERNAL_ERROR,