EDBG_DEVICE_TYPE is a property of the CPU, is should not be set by every board individually.
cpu/$(CPU)/Makefile.features and cpu/$(CPU)/Makefile.dep are automatically included Part of moving CPU/CPU_MODEL definition to Makefile.features to have it available before Makefile.include.
This adds support for the Atmel SAM E54 Xplained Pro Evaluation Kit. Only basic functionality has been enabled.