rtc: 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: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-ds1672.c

@@ -190,7 +190,7 @@ static int ds1672_probe(struct i2c_client *client,
 	return 0;
 }
 
-static struct i2c_device_id ds1672_id[] = {
+static const struct i2c_device_id ds1672_id[] = {
 	{ "ds1672", 0 },
 	{ }
 };

drivers/rtc/rtc-em3027.c

@@ -132,7 +132,7 @@ static int em3027_probe(struct i2c_client *client,
 	return 0;
 }
 
-static struct i2c_device_id em3027_id[] = {
+static const struct i2c_device_id em3027_id[] = {
 	{ "em3027", 0 },
 	{ }
 };

drivers/rtc/rtc-max6900.c

@@ -226,7 +226,7 @@ max6900_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	return 0;
 }
 
-static struct i2c_device_id max6900_id[] = {
+static const struct i2c_device_id max6900_id[] = {
 	{ "max6900", 0 },
 	{ }
 };

drivers/rtc/rtc-rv3029c2.c

@@ -868,7 +868,7 @@ static int rv3029_i2c_probe(struct i2c_client *client,
 	return rv3029_probe(&client->dev, regmap, client->irq, client->name);
 }
 
-static struct i2c_device_id rv3029_id[] = {
+static const struct i2c_device_id rv3029_id[] = {
 	{ "rv3029", 0 },
 	{ "rv3029c2", 0 },
 	{ }