The `SDK_VERSION` was incorrectly set to itself instead of keeping the
`COREBOOT_IMAGE_TAG` variable, leaving it as an empty string.
Test: Run `make coreboot-sdk` and see `SDK_VERSION` matches the tag.
Fixes: d3a89cdb749a ("util/docker: Replace use of sed with build args")
Change-Id: I4c8be7d0f7c1ac82da397e720d13a7075f22ec4d
Signed-off-by: Tim Crawford <tcrawford@system76.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78141
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Reviewed-by: Martin L Roth <gaumless@gmail.com>