am b20c2def: (-s ours) am 6707b5b7: (-s ours) hammerhead: update prebuilt kernel

* commit 'b20c2def6c363c909cc43f9cfb617b59cd0bfd24':
tree: b74aa191ac219c45a56f93a9e56a4d76bd396e4f
  1. zImage-dtb