staging: iio: tsl2x7x: constify i2c_device_id

i2c_device_id are not supposed to change at runtime. All functions
working with i2c_device_id provided by <linux/i2c.h> work with
const i2c_device_id. So mark the non-const structs as const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/light/tsl2x7x.c

@@ -1977,7 +1977,7 @@ static int tsl2x7x_remove(struct i2c_client *client)
 	return 0;
 }
 
-static struct i2c_device_id tsl2x7x_idtable[] = {
+static const struct i2c_device_id tsl2x7x_idtable[] = {
 	{ "tsl2571", tsl2571 },
 	{ "tsl2671", tsl2671 },
 	{ "tmd2671", tmd2671 },