xen-platform: constify pci_device_id.

pci_device_id are not supposed to change at runtime. All functions
working with pci_device_id provided by <linux/pci.h> work with
const pci_device_id. So mark the non-const structs as const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

drivers/xen/platform-pci.c

@@ -175,7 +175,7 @@ static int platform_pci_probe(struct pci_dev *pdev,
 	return ret;
 }
 
-static struct pci_device_id platform_pci_tbl[] = {
+static const struct pci_device_id platform_pci_tbl[] = {
 	{PCI_VENDOR_ID_XEN, PCI_DEVICE_ID_XEN_PLATFORM,
 		PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
 	{0,}