hikey-kernel: Update kernel prebuilt to Image-dtb (6d9a0bc) am: 518f7c5c65 am: 8d774793de
am: 9689eed1c6

* commit '9689eed1c61496c26fe08eb686b96d962909b875':
  hikey-kernel: Update kernel prebuilt to Image-dtb (6d9a0bc)

Change-Id: I6cf287088939406185fdd45b92c79b82131b8f95