Input: qt2160 - tweak check for i2c adapter functionality

i2c_check_functionality() returns essentially a boolean and not an error
code, so treat it as such.

Link: https://lore.kernel.org/r/20230724051345.335219-1-dmitry.torokhov@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/qt2160.c

@@ -345,12 +345,9 @@ static int qt2160_probe(struct i2c_client *client)
 	int i;
 	int error;
 
-	/* Check functionality */
-	error = i2c_check_functionality(client->adapter,
-			I2C_FUNC_SMBUS_BYTE);
-	if (!error) {
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
 		dev_err(&client->dev, "%s adapter not supported\n",
-				dev_driver_string(&client->adapter->dev));
+			dev_driver_string(&client->adapter->dev));
 		return -ENODEV;
 	}