- this prepares everything for the more boards in the family
- which will need `dt/` folder to avoid null-patches
- label & make LEDs useful
- alias mmc0/mmc1 so they match u-boot
- expose i2c3 which is exposed in the 40-pin 27:SCL3 28:SDA3 (blue pins)
- shows up at i2c1 to userspace; why would Collabora alias an undescribed bus?