pci: deassert intx when pci device unrealize

If a pci device is not reset by VM (by writing into config space)
and unplugged by VM, after that when VM reboots, qemu may assert:
pcibus_reset: Assertion `bus->irq_count[i] == 0' failed

Cc: qemu-stable@nongnu.org
Signed-off-by: herongguang <herongguang.he@huawei.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 3936161f1f)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

hw/pci/pci.c

@@ -1083,6 +1083,7 @@ static void pci_qdev_unrealize(DeviceState *dev, Error **errp)
         pc->exit(pci_dev);
     }
 
+    pci_device_deassert_intx(pci_dev);
     do_pci_unregister_device(pci_dev);
 }