HDMI display test

AIBOX-1688 supports HDMI 2.0 standard.

You can test the HDMI with following commands:

insmod /mnt/system/ko/soph_drm.ko
systemctl stop SophonHDMI.service
systemctl restart SophonHDMI.service

You can also use modetest to test:

modetest -M cvitek -s 42@40:1920x1080-60@RG24

Replace 42@40:1920x1080-60@RG24 with the actual display resolution of the display.