xen: Use dev_is_pci() to check whether it is pci device

Use PCI standard marco dev_is_pci() instead of directly compare
pci_bus_type to check whether it is pci device.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Jan Beulich <JBeulich@suse.com>

drivers/xen/dbgp.c

@@ -19,7 +19,7 @@ static int xen_dbgp_op(struct usb_hcd *hcd, int op)
 	dbgp.op = op;
 
 #ifdef CONFIG_PCI
-	if (ctrlr->bus == &pci_bus_type) {
+	if (dev_is_pci(ctrlr)) {
 		const struct pci_dev *pdev = to_pci_dev(ctrlr);
 
 		dbgp.u.pci.seg = pci_domain_nr(pdev->bus);