u-boot: add variant with disabled serial console
with meta-seconorth-machine 9dc6f5056f46dd84cc28c03b5bc3ebf0753de272 we added a second u-boot binary with disabled console output. This adds it to the release artifact.
with meta-seconorth-machine 9dc6f5056f46dd84cc28c03b5bc3ebf0753de272 we added a second u-boot binary with disabled console output. This adds it to the release artifact.