thermal/hwmon: Do not set no_hwmon before calling thermal_add_hwmon_sysfs()

The thermal->tzp->no_hwmon parameter is only used when calling
thermal_zone_device_register().

Setting it to 'false' before calling thermal_add_hwmon_sysfs() has no
effect.

Remove the call and again prevent the drivers to access the thermal
internals.

Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> #R-Car
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com> #Broadcom
Acked-by: Heiko Stuebner <heiko@sntech.de> #rockchip
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>