thermal: thermal_hwmon: Convert to hwmon_device_register_with_info()

Booting Linux on a mx6q based board leads to the following warning:

(NULL device *): hwmon_device_register() is deprecated. Please convert the
driver to use hwmon_device_register_with_info().

,so do as suggested.

Also, this results in the core taking care of creating the 'name'
attribute, so drop the code doing that from the thermal driver.

Suggested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>