Input: kxtj9 - remove unneeded retval variable

The retval variable isn't needed since isn't used in the function. Remove
the variable and just return 0 instead.

This also fixes the following make coccicheck warning:

drivers/input/misc/kxtj9.c:638:5-11: Unneeded variable: "retval". Return "0" on line 646

Signed-off-by: Javier Martinez Canillas <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/misc/kxtj9.c

···
 	struct i2c_client *client = to_i2c_client(dev);
 	struct kxtj9_data *tj9 = i2c_get_clientdata(client);
 	struct input_dev *input_dev = tj9->input_dev;
-	int retval = 0;
 
 	mutex_lock(&input_dev->mutex);
 
···
 		kxtj9_enable(tj9);
 
 	mutex_unlock(&input_dev->mutex);
-	return retval;
+	return 0;
 }
 
 static SIMPLE_DEV_PM_OPS(kxtj9_pm_ops, kxtj9_suspend, kxtj9_resume);