dt-bindings/thermal: Add property to selectively register CPU cooling devs

CPU cooling device register and handling max and min limit
functionalities are moved to cpu clock driver and cpu vdd min
voltage cooling device driver respectively. Add optional property
to selectively register CPU cooling devices for LMH DCVSh driver.

Change-Id: I0dea34a3c7f3904aaf06193a01d94f49569ecadc