x86_pkg_temp_thermal: Do not expose as a hwmon device

The temperature value reported by x86_pkg_temp_thermal is already
reported by the coretemp driver. So, do not expose this thermal zone
as a hwmon device, because it would be redundant.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <eduardo.valentin@ti.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>