hwmon: (emc1403) Remove unnecessary hwmon_device_unregister

It is unnecessary and wrong to call hwmon_device_unregister in error
handling before hwmon_device_register is called.

Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Reviewed-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: stable@kernel.org
Signed-off-by: Jean Delvare <khali@linux-fr.org>