hwmon: (ntc_thermistor) Return error code from hwmon_device_register

hwmon_device_register() never returns a NULL pointer in case of errors, but
an error value. Use it.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>
1 file changed