Merge pull request 'Update config/grub/config/grub.cfg' (#167) from...

Merge pull request 'Update config/grub/config/grub.cfg' (#167) from semigel/lbmk:semigel-btrfs-subvol-patch-1 into master

Reviewed-on: https://codeberg.org/libreboot/lbmk/pulls/167