Input: cyttsp - use PTR_ERR_OR_ZERO()

The PTR_ERR_OR_ZERO() helper function checks if a pointer contains an
errno code and returns it or return 0 if that's not the case. Use the
helper instead of open coding the same logic in the driver. This was
found with make coccicheck that complains with the following warning:

drivers/input/touchscreen/cyttsp4_i2c.c:53:1-3: WARNING: PTR_ERR_OR_ZERO can be used
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/cyttsp4_i2c.c

@@ -50,10 +50,7 @@ static int cyttsp4_i2c_probe(struct i2c_client *client,
 	ts = cyttsp4_probe(&cyttsp4_i2c_bus_ops, &client->dev, client->irq,
 			  CYTTSP4_I2C_DATA_SIZE);
 
-	if (IS_ERR(ts))
-		return PTR_ERR(ts);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(ts);
 }
 
 static int cyttsp4_i2c_remove(struct i2c_client *client)