media: radio: constify pnp_device_id

pnp_device_id are not supposed to change at runtime. All functions
working with pnp_device_id provided by <linux/pnp.h> work with
const pnp_device_id. So mark the non-const structs as const.

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>

drivers/media/radio/radio-gemtek.c

@@ -281,7 +281,7 @@ static const struct radio_isa_ops gemtek_ops = {
 static const int gemtek_ioports[] = { 0x20c, 0x30c, 0x24c, 0x34c, 0x248, 0x28c };
 
 #ifdef CONFIG_PNP
-static struct pnp_device_id gemtek_pnp_devices[] = {
+static const struct pnp_device_id gemtek_pnp_devices[] = {
 	/* AOpen FX-3D/Pro Radio */
 	{.id = "ADS7183", .driver_data = 0},
 	{.id = ""}