acerhdf: Drop pointless dependency on THERMAL_HWMON

The THERMAL_HWMON config option simply exposes the thermal zone
temperature values and limits to user-space. It makes no sense for a
kernel driver to depend on this.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Peter Feuerer <peter@piie.net>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>