hwmon: (acpi_power_meter) Use return value from acpi_bus_register_driver

acpi_bus_register_driver() returns a valid error code. Use it.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c
index 51b045b..8d40da3 100644
--- a/drivers/hwmon/acpi_power_meter.c
+++ b/drivers/hwmon/acpi_power_meter.c
@@ -996,7 +996,7 @@
 
 	result = acpi_bus_register_driver(&acpi_power_meter_driver);
 	if (result < 0)
-		return -ENODEV;
+		return result;
 
 	return 0;
 }