Input: sx8654 - fix memory allocation check

We have been testing wrong variable when trying to make sure that input
allocation succeeded.

Reported by Coverity (CID 1295918).
Acked-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/sx8654.c

@@ -187,7 +187,7 @@ static int sx8654_probe(struct i2c_client *client,
 		return -ENOMEM;
 
 	input = devm_input_allocate_device(&client->dev);
-	if (!sx8654)
+	if (!input)
 		return -ENOMEM;
 
 	input->name = "SX8654 I2C Touchscreen";