Add 'sys/contrib/device-tree/' from commit '5ee353c36d3c9c7f63df7c7671875e73fba70958'

git-subtree-dir: sys/contrib/device-tree
git-subtree-mainline: 94611a838866cba8d7366a3107724af98c75e953
git-subtree-split: 5ee353c36d3c9c7f63df7c7671875e73fba70958