thermal: Fix polling frequency for systems without passive cooling

The polling interval (in deciseconds) was accidently interpreted as
being in milliseconds in one codepath, resulting in excessively frequent
polling. Ensure that the conversion is performed.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>