treewide: remove support for yocto hardknott Remove hardknott to be compatible with upstream change: https://gerrit.openbmc-project.xyz/c/openbmc/openbmc/+/51576/ Signed-off-by: Hao Jiang <jianghao@google.com> Change-Id: I624c2c36c9bd01df293ff8cce2eda18e354d86ac