Dasharo: put coreboot config in defconfig to show settings that needed to be changed from kconfig defaults

repro:
./docker_repro.sh make BOARD=novacustom-v540tu coreboot.save_in_defconfig_format_in_place
./docker_repro.sh make BOARD=novacustom-v560tu coreboot.save_in_defconfig_format_in_place
./docker_repro.sh make BOARD=novacustom-nv4x_adl coreboot.save_in_defconfig_format_in_place

Signed-off-by: Thierry Laurion <insurgo@riseup.net>

Author: tlaurion