Merge "Remove stale SYSTEM_ROOT_IMAGE board config for old kernels" am: 59d1eb18e3 am: d71676c3f3

Original change: https://android-review.googlesource.com/c/device/linaro/hikey/+/2176482

Change-Id: If7c99983ba389b18c3939bbf2ce42a837e59be27
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>