What Happens if a Device Is In a Device Tree but Not Physically Present
A device can fail anytime, and drivers have to handle such problems gracefully. So, don't oops and and don't run into endless loops. Instead, report an error code to userspace or upstream device driver. (This usually isn't a problem unless a device has VM-mapped RAM or doing DMA transfers.)

The purpose of the device tree is to take the knowledge of individual board designs out of the drivers, so one driver can handle any board which has a certain kind of device on it.

If you never plan to attach a certain I²C chip to the board, it's best to remove it from the device tree definition and recompile. If it's optional, you better place it into an overlay file so the user can decide if he had that hardware or not.

Look for the Raspberry Pi device tree stuff, it has numerous overlays for all kind of stuff to attach.