Beaglebone-AI64: Add PMIC control

[nmenon]

https://lore.kernel.org/linux-arm-kernel/20230727130908.10656-1-eblanc@baylibre.com/

Once merged, look to add PMIC support so that poweroff, reboot etc properly work. maybe cpufreq can control vdd_mpu? need to cross check schematics.

[sukrutb]

I can work on this.

[nmenon]

Thanks Sukrut - assigned.