hwmon: (acpi_power_meter) Fix acpi_bus_get_device() return value check

Since acpi_bus_get_device() returns plain int and not acpi_status,
ACPI_FAILURE() should not be used for checking its return value.  Fix
that.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>