s390/pci: do not modify function handles

Don't modify function handles to get a disabled handle - call
clp_disable_fh. With this change we also do no longer deconfigure
enabled functions.

Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci.c

@@ -955,6 +955,13 @@ out:
 }
 EXPORT_SYMBOL_GPL(zpci_enable_device);
 
+int zpci_disable_device(struct zpci_dev *zdev)
+{
+	zpci_dma_exit_device(zdev);
+	return clp_disable_fh(zdev);
+}
+EXPORT_SYMBOL_GPL(zpci_disable_device);
+
 int zpci_create_device(struct zpci_dev *zdev)
 {
 	int rc;