arm: mach-k3: am62: Fixup thermal zone critical points

Read the max temperature for the SoC temperature grade from the hardware
and change the critical trip nodes on each thermal zone of FDT at
runtime so they are correct with the hardware value for its grade.

Signed-off-by: Joao Paulo Goncalves <joao.goncalves@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>