i2c-0 is the bus the AXP209 is attached to, we don't have access to that bus for our use.
The 4.3 kernel DTS does have the appropriate i2c-1 settings that can be copied over to 4.4. I would only copy the i2c-1 related stuff, leaving everything else in 4.4 as it is currently setup.
i2c-1 will be coming back as default in an upcoming OS drop I believe. The keyboard for the PocketCHIP is attached to i2c-1, so it'll need to be around for the ability to remove CHIP from PocketCHIP and use standalone, and vice-versa.