mvebu: improve thermal management of IEI Puzzle devices

mvebu: improve thermal management of IEI Puzzle devices

 - Make step_wise thermal governor respect hysteresis
   This is done by importing a downstream patch, backporting the same feature
   now present in Linux v6.10+ would be too messy.
 - Introduce thermal zone for the WT61P803 uC (chassis and board sensors)
 - Introduce thermal zones for AQR NBase-T PHYs
 - No longer modify existing SoC thermal zones (which are now only in charge
   for emergency shutdown, and can be interrupt driven instead of polled)

Signed-off-by: Daniel Golle <[email protected]>
Signed-off-by: Christian Marangi <[email protected]>