thermal_hwmon: Sanitize thermal_zone type

When calling thermal_add_hwmon_sysfs(), the device type is sanitized by
replacing '-' with '_'. However tz->type remains unsanitized. Thus
calling thermal_hwmon_lookup_by_type() returns no device. And if there is
no device, thermal_remove_hwmon_sysfs() fails with "hwmon device lookup
failed!".

The result is unregisted hwmon devices in the sysfs.

Fixes: 409ef0ba ("thermal_hwmon: Sanitize attribute name passed to hwmon")

Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>