i2c: taos-evm: Remove duplicate NULL check

Since i2c_unregister_device() became NULL-aware we may remove duplicate
NULL check.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-taos-evm.c

@@ -282,8 +282,7 @@ static void taos_disconnect(struct serio *serio)
 {
 	struct taos_data *taos = serio_get_drvdata(serio);
 
-	if (taos->client)
-		i2c_unregister_device(taos->client);
+	i2c_unregister_device(taos->client);
 	i2c_del_adapter(&taos->adapter);
 	serio_close(serio);
 	kfree(taos);