empty vconsole.keymap by default as kernel parameter

There are an empty vconsole.keymap= kernel parameter by default. I'm unable to override that. It's mandatory to set kerboard layout for luks decrypt

https://bootc-dev.github.io/bootc/building/kernel-arguments.html?highlight=kerne#usrlibbootckargsd add a duplicate instead of replacing it. It's probably a bootc issue but it's maybe easy to remove from image.