Change in coreboot[master]: RISC-V boards: Stop using the config string

[build bot (Jenkins) (Code Review)]

build bot (Jenkins) has posted comments on this change. ( https://review.coreboot.org/21690 )

Change subject: RISC-V boards: Stop using the config string
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Patch Set 3: Verified+1

Build Successful

https://qa.coreboot.org/job/coreboot-gerrit/61334/ : SUCCESS

https://qa.coreboot.org/job/coreboot-checkpatch/16478/ : SUCCESS