hwmon: (asus_atk0110) Check ACPI_COMPANION() against NULL

Every platform driver can be forced to match a device that doesn't match
its list of device IDs because of device_match_driver_override(), so
platform drivers that rely on the existence of a device's ACPI companion
object need to verify its presence.

Accordingly, add a requisite ACPI_HANDLE() check against NULL to the
asus_atk0110 hwmon driver.

Fixes: ee17525 ("hwmon: (asus_atk0110) Convert ACPI driver to a platform one")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/2261594.irdbgypaU6@rafael.j.wysocki
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Author: rafaeljw

drivers/hwmon/asus_atk0110.c

@@ -1273,15 +1273,20 @@ static int atk_probe(struct platform_device *pdev)
 	struct acpi_buffer buf;
 	union acpi_object *obj;
 	struct atk_data *data;
+	acpi_handle handle;
 
 	dev_dbg(&pdev->dev, "adding...\n");
 
+	handle = ACPI_HANDLE(&pdev->dev);
+	if (!handle)
+		return -ENODEV;
+
 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
 	data->dev = &pdev->dev;
-	data->atk_handle = ACPI_HANDLE(&pdev->dev);
+	data->atk_handle = handle;
 	INIT_LIST_HEAD(&data->sensor_list);
 	data->disable_ec = false;