ACPI thermal: Check for thermal zone requirement

ACPI spec says (11.5 Thermal Zone Interface Requirements):
   A thermal zone must contain at least one trip point
   (critical, near critical, active, or passive)

Check this once at init time.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Tested-by:  <clarkt@cnsp.com>
Signed-off-by: Len Brown <len.brown@intel.com>