platform/x86: toshiba_bluetooth: 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_COMPANION() check against NULL to the
platform/x86 toshiba_bluetooth driver.

Fixes: 553b2ac ("platform/x86: toshiba_bluetooth: Convert ACPI driver to a platform one")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/2715450.Lt9SDvczpP@rafael.j.wysocki
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Author: rafaeljw

drivers/platform/x86/toshiba_bluetooth.c

@@ -230,10 +230,14 @@ static int toshiba_bt_resume(struct device *dev)
 
 static int toshiba_bt_rfkill_probe(struct platform_device *pdev)
 {
-	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 	struct toshiba_bluetooth_dev *bt_dev;
+	struct acpi_device *device;
 	int result;
 
+	device = ACPI_COMPANION(&pdev->dev);
+	if (!device)
+		return -ENODEV;
+
 	result = toshiba_bluetooth_present(device->handle);
 	if (result)
 		return result;