IA64: PCI: dont disable irq which is not enabled

This patch prevents pcibios_disable_device() from disabling interrupts
of devices which is not enabled.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: MUNEDA Takahiro <muneda.takahiro@jp.fujitsu.com>
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

arch/ia64/pci/pci.c

@@ -562,6 +562,7 @@ pcibios_enable_device (struct pci_dev *dev, int mask)
 void
 pcibios_disable_device (struct pci_dev *dev)
 {
+	if (dev->is_enabled)
 		acpi_pci_irq_disable(dev);
 }