hikey-kernel: Update kernel prebuilt to Image-dtb (6d9a0bc) am: 518f7c5c65
am: 8d774793de

* commit '8d774793decbbe27091e2f47b865acd07d73f8b7':
  hikey-kernel: Update kernel prebuilt to Image-dtb (6d9a0bc)

Change-Id: I8b2fd5cb0ea03daba630c961808c9af46b529c83