Suspend / resume support

[hajimen]

I am very interested in suspend / resume support. But for now, apparently Milk-V Duo doesn't have it. I hope Milk-V Duo gets it.

Refs:

• https://community.milkv.io/t/suspend-resume-support/2200
• https://www.cnx-software.com/2024/03/25/duo-s-risc-v-arm-sbc-features-sophgo-sg2000-soc-ethernet-wifi-6-and-bluetooth-5-connectivity/#comment-616647