Input: atlas - 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
atlas_btns driver.

Fixes: b830388 ("Input: atlas - convert ACPI driver to a platform one")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/8696590.T7Z3S40VBb@rafael.j.wysocki
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: rafaeljw

drivers/input/misc/atlas_btns.c

@@ -60,11 +60,15 @@ static acpi_status acpi_atlas_button_handler(u32 function,
 
 static int atlas_acpi_button_probe(struct platform_device *pdev)
 {
-	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
+	struct acpi_device *device;
 	acpi_status status;
 	int i;
 	int err;
 
+	device = ACPI_COMPANION(&pdev->dev);
+	if (!device)
+		return -ENODEV;
+
 	input_dev = input_allocate_device();
 	if (!input_dev) {
 		pr_err("unable to allocate input device\n");