hikey-kernel: Update prebuilt kernel to 4.4.8 (956a9dd) am: 78e2e21bb4
am: e8461c9f05

* commit 'e8461c9f05b63b351a14e51a877c9a5c68a40cd8':
  hikey-kernel: Update prebuilt kernel to 4.4.8 (956a9dd)

Change-Id: I36f32c512c0edaa674311af5b0d587fe586cb958