rtc: m41t80: simplify getting the adapter of a client

We have a dedicated pointer for that, so use it. Much easier to read and
less computation involved.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-m41t80.c

@@ -876,7 +876,7 @@ static struct notifier_block wdt_notifier = {
 static int m41t80_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
-	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+	struct i2c_adapter *adapter = client->adapter;
 	int rc = 0;
 	struct rtc_time tm;
 	struct m41t80_data *m41t80_data = NULL;