Remove all support for generating the device tree (FDT)

[et-tommythorn]

Dromajo is primarily targeted a use case where an existing FDT will already exist. Keeping the FDT generation became awkward and a pitfall as it could conflict with an already provided one.

[et-tommythorn]

Sigh. This has consequences and runs into other problems with dromajo not originally being designed as a library. In an ideal world, the configuration parsing and fdt generation would be optional parts that a library client could call if desired, not something deeply embedded into the initialization. However, this clean up is out of scope of the original change.