thermal: devfreq_cooling: remove old power model and use EM

Remove old power model and use new Energy Model to calculate the power
budget. It drops static + dynamic power calculations and power table
in order to use Energy Model performance domain data. This model
should be easy to use and could find more users. It is also less
complicated to setup the needed structures.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>