media: drv-intf: saa7146: 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.
So making 'pci_tbl' as const member of 'struct saa7146_extension'.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

include/media/drv-intf/saa7146.h

@@ -96,7 +96,7 @@ struct saa7146_extension
 	   supported devices, last entry 0xffff, 0xfff */
 	struct module *module;
 	struct pci_driver driver;
-	struct pci_device_id *pci_tbl;
+	const struct pci_device_id *pci_tbl;
 
 	/* extension functions */
 	int (*probe)(struct saa7146_dev *);